Method and circuitry to determine the relaxation time of a battery/cell

ABSTRACT

The present inventions, in one aspect, are directed to techniques and/or circuitry to adaptively charge a battery/cell using data which is representative of a change in terminal voltage of the battery/cell. In another aspect, the present inventions are directed to techniques and/or circuitry to adaptively charge a battery/cell using data which is representative of partial and/or full relaxation time of the battery/cell. In yet another aspect the present inventions are directed to techniques and/or circuitry to determine whether the data which is representative of partial and/or full relaxation time exceeds a predetermined range and/or is greater than a predetermined value.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/615,491, entitled “Method and Circuitry to Adaptively Charge aBattery/Cell”, filed Feb. 6, 2015, which is a divisional of U.S.application Ser. No. 14/161,755, entitled “Method and Circuitry toAdaptively Charge a Battery/Cell”, filed Jan. 23, 2014, now U.S. Pat.No. 8,975,874, which is a divisional of U.S. application Ser. No.13/111,902, entitled “Method and Circuitry to Adaptively Charge aBattery/Cell”, filed May 19, 2011, now U.S. Pat. No. 8,638,070, whichclaims priority to: (1) U.S. Provisional App. Ser. No. 61/346,953,entitled “Method and Circuitry to Control the Charging of a RechargeableBattery”, filed May 21, 2010, (2) U.S. Provisional App. Ser. No.61/358,384, entitled “Method and Circuitry to Measure the State ofCharge and Impedance of a Rechargeable Battery and to Adaptively Controlthe Charging of Same”, filed Jun. 24, 2010, (3) U.S. Provisional App.Ser. No. 61/368,158, entitled “Method and Circuitry to Adaptively Chargea Rechargeable Battery”, filed Jul. 27, 2010, (4) U.S. Provisional App.Ser. No. 61/439,400, entitled “Method and Circuitry to Adaptively Chargea Battery/Cell”, filed Feb. 4, 2011, and (5) U.S. Provisional App. Ser.No. 61/468,051, entitled “Method and Circuitry to Charge a Battery/CellUsing the State of Health Thereof and Measure the State of Health of aBattery/Cell”, filed Mar. 27, 2011 (collectively “the Provisional PatentApplications”, each of which above-identified applications areincorporated herein by reference in their entirety.

INTRODUCTION

The present inventions relate to methods and circuitry to adaptivelycharge a battery/cell. In one aspect, the present inventions aredirected to techniques and/or circuitry to adaptively charge abattery/cell using data which is representative of a change in terminalvoltage of the battery/cell. In yet another aspect, the presentinventions are directed to techniques and/or circuitry to adaptivelycharge a battery/cell using data which is representative of a partialrelaxation time of the battery/cell. In another aspect the presentinventions are directed to techniques and/or circuitry to adaptivelycharge a battery/cell using data which is representative of anoverpotential or full relaxation time of the battery/cell. In anotheraspect the present inventions are directed to techniques and/orcircuitry to adaptively charge a battery/cell using data which isrepresentative of a state of charge of the battery/cell. In anotheraspect the present inventions are directed to techniques and/orcircuitry to adaptively charge a battery/cell using data which isrepresentative of a state of health of the battery/cell.

In one embodiment, the adaptive charging techniques and/or circuitryuses and/or employs such data, in connection with certain constraints orrequirements (that will be described below) to change, adjust, controland/or vary the charging current signal(s), including thecharacteristics thereof (including, for example, shape of charge and/ordischarge signal (if any), amplitude thereof, duration thereof, dutycycle thereof and/or rest period (if any)), applied to the terminals ofthe battery/cell.

In certain embodiments, two considerations in connection withimplementing adaptive charging circuitry and techniques include (i)minimizing and/or reducing total charging time and (ii) maximizingand/or increasing cycle life. In this regard, for practical reasons, thebattery/cell is charged within a given period of time (for example, amaximum allowed period of time). Typically, a specification value isdefined or chosen depending on the application. For example, it isapproximately 2 to 4 hours for batteries employed in consumerapplications, and for batteries employed in transportation applications,it may be up to 8 hours. This results in a specification for a neteffective average charging current over the duration of the chargingperiod.

In addition, to maximize and/or increase cycle life of the battery/cell,it may be desirable to charge the battery/cell (i) at a lower currentand/or (ii) provide rest periods between or in periods of charging (forexample, between charging signals or packets) wherein no charge isapplied to or injected into the battery/cell. Thus, in certain aspects,the charging circuitry of the present inventions implement adaptivetechniques which seek to (i) minimize and/or reduce total charging timeof the battery/cell and (ii) maximize and/or increase the cycle life ofthe battery/cell (by, for example, minimizing and/or reducingdegradation mechanisms of the charging operation).

The present inventions also relate to techniques or methods ofestimating, measuring, calculating, assessing and/or determiningcharacteristics or parameters of the battery/cell including, forexample, a terminal voltage (and/or changes therein) of a battery/cell,state of charge (and/or changes therein) of a battery/cell, and/or arelaxation time (and/or changes therein) of a battery/cell, a state ofhealth (and/or changes therein) of a battery/cell. Notably, data whichis representative of characteristics or parameters of the battery/cell(for example, the state of charge, relaxation time, impedance, state ofhealth and/or terminal voltage) may be dependent on temperature. Withthat in mind in the discussion below, in connection with circuitry andtechniques for adaptively charging a battery, it will be implicit thatthere may be a dependence on temperature. As such, while temperature maynot be necessarily mentioned below, such data may be dependent on thetemperature of the battery

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of the detailed description to follow, reference will bemade to the attached drawings. These drawings show different aspects ofthe present inventions and, where appropriate, reference numeralsillustrating like structures, components, materials and/or elements indifferent figures are labeled similarly. It is understood that variouscombinations of the structures, components, and/or elements, other thanthose specifically shown, are contemplated and are within the scope ofthe present inventions.

Moreover, there are many inventions described and illustrated herein.The present inventions are neither limited to any single aspect norembodiment thereof, nor to any combinations and/or permutations of suchaspects and/or embodiments. Moreover, each of the aspects of the presentinventions, and/or embodiments thereof, may be employed alone or incombination with one or more of the other aspects of the presentinventions and/or embodiments thereof. For the sake of brevity, certainpermutations and combinations are not discussed and/or illustratedseparately herein.

FIGS. 1A-1C illustrate block diagram representations of exemplaryadaptive charging circuitry in conjunction with a battery/cell,according to at least certain aspects of certain embodiments of thepresent inventions, wherein FIG. 1B includes discrete memory coupled tothe control circuitry, and FIG. 1C illustrates circuitry external whichaccesses the memory to store one or more predetermined ranges employedby control circuitry in conjunction with adapting, adjusting and/orcontrolling one or more characteristics of the charge or current appliedto or injected into the battery/cell so that a change in voltage at theterminals of the battery/cell in response to such charge or current iswithin a predetermined range and/or below a predetermined value during acharging or recharging sequence, operation or cycle;

FIG. 1D illustrates, in block diagram form, exemplary adaptive chargingcircuitry in conjunction with a battery/cell (which may include twoterminals (for example, positive and negative terminals), according toat least certain aspects of certain embodiments of the presentinventions, wherein in this embodiment, the charging circuitry mayinclude voltage source and/or current source, and the monitoringcircuitry may include voltage and/or current sensors (for example, avoltmeter and/or a current meter);

FIGS. 2A-2D illustrate exemplary waveforms illustrating a plurality ofexemplary charging signals and discharging signals of an exemplarycharging technique, wherein such charging signals may generally decreaseaccording to a predetermined rate and/or pattern (for example,asymptotically, linearly or quadratically) as the terminal voltage ofthe battery/cell increases during a charging or recharging sequence,operation or cycle (see, FIGS. 2B and 2D); notably, a charging orrecharging sequence, operation or cycle may include charging signals(which, in total, inject or apply charge into the battery/cell) anddischarging signals (which, in total, remove charge from thebattery/cell);

FIGS. 3A-3N illustrate exemplary charge and/or discharge packets of thecharging and discharging signals (which are exemplary illustrated inFIGS. 2A-2D), wherein such charge and discharge packets may include oneor more charge pulses and one or more discharge pulses; notably, in oneembodiment, each charge signal of FIGS. 2A-2D may include a plurality ofpackets (for example, about 100 to about 50,000 packets) and, in oneembodiment, each packet may include a plurality of charge pulses,discharge pulses and rest periods; notably, the pulses may be any shape(for example, rectangular, triangle, sinusoidal or square); in oneexemplary embodiment, the charge and/or discharge pulses of the packetmay include a temporal duration of between about 1 ms to about 500 ms,and preferably less than 50 ms; moreover, as discussed in detail below,one, some or all of the characteristics of the charge and dischargepulses (for example, pulse amplitude, pulse width/duration and pulseshape) are programmable and/or controllable via charging circuitrywherein the amplitude of the positive and/or negative pulses may varywithin the packet (and are programmable and/or controllable), theduration and/or timing of the rest periods may vary within the packet(and are programmable and/or controllable) and/or, in addition, suchpulses may be equally or unequally spaced within the packet; thecombination of charging pulses, discharging pulses and rest periods maybe repetitive and thereby forms a packet that may be repeated; allcombination or permutations of pulse, pulse characteristics, periods,packets and signal characteristics and configurations are intended tofall within the scope of the present inventions;

FIG. 4A is a flowchart of an exemplary process of determining, adaptingand/or controlling the characteristics of a charging current based on orusing a change in voltage at the terminals of the battery/cell inresponse to a charge packet (which may include one or more charge pulsesand one or more discharge pulses), according to certain aspects of thepresent inventions; wherein the charging techniques and/or circuitryadapt, adjust and/or control one or more characteristics of the chargeor current applied to or injected into the battery/cell so that thechange in voltage at the terminals of the battery/cell in response toone or more subsequent charge packets is within a predetermined rangeand/or below a predetermined value during a charging or rechargingsequence, operation or cycle;

FIG. 4B is a flowchart of an exemplary process of adaptively determiningthe characteristics of the discharging current based on or using achange in voltage at the terminals of the battery/cell in response to adischarge packet (which may include one or more discharge pulses and oneor more charge pulses), according to certain aspects of the presentinventions; wherein the discharging techniques and/or circuitry adapt,adjust and/or control one or more characteristics of the charge orcurrent removed from the battery/cell so that the change in voltage atthe terminals of the battery/cell in response to one or more subsequentdischarge packets is within a predetermined range and/or below apredetermined value during a charging sequence, operation or cycle;

FIG. 5A illustrates an exemplary charge packet having a charge pulseincluding a charging period (T_(charge)) followed by a rest period(T_(rent)) wherein the period of the charge packet is identified asT_(packet), according to certain aspects of the present inventions; anexemplary terminal voltage response of the battery/cell to such chargepacket is illustrated wherein a first voltage (V₁) is identified (whichcorrelates to the beginning of the charge pulse), a second voltage (V₂)is identified (which correlates to the end of the charge pulse and/orthe peak of the change in the terminal voltage due to the charge pulse)and a third voltage (V₃) is identified (which correlates to the end ofthe charge packet, the beginning of an immediately subsequent packet(for example, charge or discharge packet) and/or the end of the restperiod of the charge packet);

FIG. 5B illustrates an exemplary charge packet having a charge pulse(which injects charge into the battery/cell) and a discharge pulse(which removes charge from the battery/cell) wherein the charge pulseincludes a charging period (T_(charge)) and the discharge pulse includesa discharging period (T_(discharge)), according to certain aspects ofthe present inventions; notably, in this exemplary charge packet, anintermediate rest period (T_(inter)) is disposed between the charge anddischarge pulses, and a rest period (T_(rest)) is disposed after thedischarge pulse and before the next packet; an exemplary terminalvoltage response of the battery/cell to such charge packet isillustrated wherein a first voltage (V₁) is identified (which correlatesto the beginning of the charge pulse), a second voltage (V₂) isidentified (which correlates to the end of the charge pulse and/or thepeak of the change in the terminal voltage due to the charge pulse), athird voltage (V₃) is identified (which correlates to the beginning ofthe discharge pulse), a fourth voltage (V₄) is identified (whichcorrelates to the end of the discharge pulse and/or the peak of thechange in the terminal voltage due to the discharge pulse) and a fifthvoltage (V₅) is identified (which correlates to the end of the chargepacket, the beginning of an immediately subsequent packet (for example,charge or discharge packet) and/or the end of the rest period of thecharge packet); notably, as discussed in detail below, one, some or allof the characteristics of the charge pulses (for example, pulseamplitude, pulse width/duration and pulse shape) are programmable and/orcontrollable via charging circuitry wherein the amplitude of thepositive and/or negative pulses may vary within the packet (and areprogrammable and/or controllable), the duration and/or timing of therest periods may vary within the packet (and are programmable and/orcontrollable) and/or, in addition, such pulses may be equally orunequally spaced within the packet; the combination of charging pulses,discharging pulses and rest periods may be repetitive and thereby formsa packet that may be repeated; all combination or permutations of pulse,pulse characteristics, periods, packets and signal characteristics andconfigurations are intended to fall within the scope of the presentinventions; moreover, discharge packets may have similar characteristicsas charge packets except, however, a net charge is removed from thebattery/cell; for the sake of brevity, the discussion/illustration withrespect to discharge packet will not be repeated;

FIG. 6A illustrates an exemplary charge packet having a charge pulsewherein the amplitude of the charge pulse is greater than the amplitudeof the charge pulse of FIG. 5A wherein the charging circuitry, inresponse to instructions from the control circuitry, adjust theamplitude of the charge pulse to increase the responsive terminalvoltage so that the change in terminal voltage of the battery/cell iswithin a predetermined range and/or below a predetermined value during acharging or recharging sequence, operation or cycle; an exemplaryterminal voltage response of the battery/cell to such a charge pulse isillustrated wherein a first voltage (V₁) is identified (which correlatesto the beginning of the charge pulse) and a second voltage (V_(2′)) isidentified (which correlates to the end of the charge pulse and/or thepeak of the change in the terminal voltage due to the charge pulse)wherein the amplitude of the responsive terminal voltage is greater thanthe amplitude of the terminal voltage of the battery/cell which isresponsive to the charge pulse of FIG. 5A;

FIG. 6B illustrates an exemplary charge packet having a charge pulsewherein the amplitude of the charge pulse is less than the amplitude ofthe charge pulse of FIG. 5A wherein the charging circuitry, in responseto instructions from the control circuitry, adjust the amplitude of thecharge pulse to decrease the responsive terminal voltage so that thechange in terminal voltage of the battery/cell is within a predeterminedrange and/or below a predetermined value during a charging or rechargingsequence, operation or cycle; an exemplary terminal voltage response ofthe battery/cell to such a charge pulse is illustrated wherein a firstvoltage (V₁) is identified (which correlates to the beginning of thecharge pulse) and a second voltage (V_(2′)) is identified (whichcorrelates to the end of the charge pulse and/or the peak of the changein the terminal voltage due to the charge pulse) wherein the amplitudeof the responsive terminal voltage is less than the amplitude of theterminal voltage of the battery/cell which is responsive to the chargepulse of FIG. 5A;

FIG. 7 illustrates of three exemplary changes in net effective chargingcurrent of a battery/cell over time (which, in one embodiment, is afunction of the state of charge of the battery/cell), according tocertain aspects of the present inventions;

FIG. 8 is an exemplary illustration of the relaxation time as functionof state of charge of a battery/cell (rated at 2.5 A.h); notably, thedata was acquired using a square-like charging pulse having duration of20 ms;

FIG. 9A illustrates an exemplary charge packet having two charge pulses(each including a charging period (T_(charge))) followed by a restperiod (T_(rest)) wherein the period of the charge packet is identifiedas T_(packet), according to certain aspects of the present inventions;an exemplary terminal voltage response of the battery/cell to suchcharge packet is illustrated wherein a first voltage (V₁) is identified(which correlates to the beginning of the first charge pulse and, inthis embodiment, the beginning of the packet), a second voltage (V₂) isidentified (which correlates to the end of the first charge pulse and/orthe peak of the change in the terminal voltage due to the first chargepulse), a third voltage (V₃) is identified (which correlates to thebeginning of the second charge pulse), a fourth voltage (V₄) isidentified (which correlates to the end of the second charge pulseand/or the peak of the change in the terminal voltage due to the secondcharge pulse) and a fifth voltage (V₅) is identified (which correlatesto when the terminal voltage of the battery/cell decays to apredetermined value (for example, preferably less than 10% of peakdeviation relative to the terminal voltage of the battery/cell when thecharge/discharge packet is applied (here, V₁) and, more preferably, lessthan 5% of such peak deviation); wherein the partial relaxation time ofthe battery/cell due to the exemplary charge packet is the amount oftime between (i) the termination/end of the second charge pulse and/orthe peak of the change in the terminal voltage due to the second chargepulse and (ii) when the terminal voltage of the battery/cell decays to apredetermined value (for example, preferably less than 10% of peakdeviation and, more preferably, less than 5% of peak deviation);

FIG. 9B illustrates an exemplary charge packet having a charge pulse(which injects charge into the battery/cell) and a discharge pulse(which removes charge from the battery/cell) wherein the charge pulseincludes a charging period (T_(charge)) and the discharge pulse includesa discharging period (T_(discharge)), according to certain aspects ofthe present inventions; notably, in this exemplary charge packet, anintermediate rest period (T_(inter)) is disposed between the charge anddischarge pulses, and a rest period (T_(rest)) is disposed after thedischarge pulse and before the next packet; an exemplary terminalvoltage response of the battery/cell to such charge packet isillustrated wherein a first voltage (V₁) is identified (which correlatesto the beginning of the charge pulse and, in this embodiment, thebeginning of the packet), a second voltage (V₂) is identified (whichcorrelates to the end of the charge pulse and/or the peak of the changein the terminal voltage due to the charge pulse), a third voltage (V₃)is identified (which correlates to the end of the discharge pulse and/orthe peak of the change in the terminal voltage due to the dischargepulse) and a fourth voltage (V₄) is identified (which correlates to whenthe terminal voltage of the battery/cell decays to a predetermined value(for example, preferably less than 10% of peak deviation relative to theterminal voltage of the battery/cell when the charge/discharge packet isapplied (here, V₁) and, more preferably, less than 5% of peakdeviation); wherein the relaxation time of the battery/cell due to theexemplary charge packet is the amount of time between (i) thetermination/end of the discharge pulse and/or the peak of the change inthe terminal voltage due to the discharge pulse (see, V₃ and T₁) and(ii) when the terminal voltage of the battery/cell decays to apredetermined value (for example, preferably less than 10% of peakdeviation and, more preferably, less than 5% of peak deviation) (see, V₄and T₂); notably, as discussed in detail herein, one, some or all of thecharacteristics of the charge pulses (for example, pulse amplitude,pulse width/duration and pulse shape) are programmable and/orcontrollable via charging circuitry wherein the amplitude of thepositive and/or negative pulses may vary within the packet (and areprogrammable and/or controllable), the duration and/or timing of therest periods may vary within the packet (and are programmable and/orcontrollable) and/or, in addition, such pulses may be equally orunequally spaced within the packet; the combination of charging pulses,discharging pulses and rest periods may be repetitive and thereby formsa packet that may be repeated; all combination or permutations of pulse,pulse characteristics, periods, packets and signal characteristics andconfigurations are intended to fall within the scope of the presentinventions; moreover, discharge packets may have similar characteristicsas charge packets except, however, a net charge is removed from thebattery/cell; for the sake of brevity, the discussion/illustration withrespect to discharge packet will not be repeated;

FIG. 9C illustrates an exemplary charge packet like that of FIG. 9Bwherein the packet includes a charge pulse (which injects charge intothe battery/cell) and a discharge pulse (which removes charge from thebattery/cell) wherein the charge pulse includes a charging period(T_(charge)) and the discharge pulse includes a discharging period(T_(discharge)), according to certain aspects of the present inventions;in this illustration, a partial relaxation time corresponding to thecharge pulse of the packet is also depicted (see, Relaxation time_(AB))wherein the relaxation time associated with the charge pulse is equal tothe difference between T_(A) (which coincides with V₂) and T_(B) (whichcoincides with V_(4′)); notably, the relaxation time of the battery/cellin response to the charge packet having a charge pulse and dischargepulse may be shorter than the relaxation time of the battery/cell inresponse to the charge packet not having a discharge pulse (compareΔT_(BA) and ΔT₂₁) and, as such, under certain circumstances, the totalcharging time of a charging sequence employing packets having charge anddischarge pulses may be shorter than the charging time of a chargingsequence employing packets having no discharge pulses to shorten orreduce the relaxation time;

FIGS. 10A-10F are flowcharts of an exemplary processes of determining,adapting and/or controlling the characteristics of a charging currentbased on, using and/or in accordance with relaxation time of thebattery/cell in response to a charge packet (which may include one ormore charge pulses and/or one or more discharge pulses) and/or dischargepacket (which may include one or more charge pulses and/or one or moredischarge pulses), according to certain aspects of the presentinventions; wherein the charging techniques and/or circuitry adapt,adjust and/or control one or more characteristics of the charge and/ordischarge pulses of one or more charge or discharge packets based on,using and/or in accordance with partial relaxation time of thebattery/cell; notably, charging techniques and/or circuitry may employdata which is representative of the partial or full relaxation time todetermine, calculate and/or estimate the state of charge of thebattery/cell (see, for example, FIGS. 10E and 10F);

FIG. 11 is an illustration depicting three responses to a charge packethaving a charge pulse (which injects charge into the battery/cell) and adischarge pulse (which removes charge from the battery/cell) wherein afirst response (A) includes a significant “overshoot” whereby thedischarge pulse removed too little charge from the battery/cell, asecond response (B) that include no significant “overshoot” or“undershoot” wherein the discharge pulse removes a suitable amount ofcharge which provides the fastest partial relaxation time of the threeresponses, and a third response (C) includes a significant “undershoot”whereby the discharge pulse removed is too much charge from thebattery/cell;

FIG. 12 is a flowchart of an exemplary process of determining, adaptingand/or controlling the characteristics of a charging current based on,using and/or in accordance with (i) a change in voltage at the terminalsof the battery/cell in response to a charge or discharge packet (whichmay include one or more charge pulses and/or one or more dischargepulses) and (ii) partial relaxation time of the battery/cell in responseto a charge or discharge packet, according to certain aspects of thepresent inventions; wherein the charging techniques and/or circuitryadapt, adjust and/or control one or more characteristics of the chargeand/or discharge pulses of one or more charge or discharge packets basedon, using and/or in accordance with a change in voltage at the terminalsof the battery/cell in response to one or more packets and the partialrelaxation time of the battery/cell in response to such one or morepackets;

FIG. 13A illustrates the partial relaxation of the terminal voltage ofthe battery/cell following the application of a charging current pulsebased on or at three different states of charge values of an exemplarybattery/cell (a commercial lithium oxide cobalt cell rated at 2.5 A.h);notably, the relaxation curves are distinctly different; a 4.20A-current pulse is 734 ms in duration; the voltage difference ismeasured relative to a “resting” open circuit voltage immediatelypreceding application of the current pulse to the battery/cell;

FIG. 13B illustrates the peak increase in voltage of the battery/celldescribed in FIG. 13A, following the application of a 2.5-A, 734 mspulse, as a function of the state of charge of the battery/cell;

FIG. 14A illustrates an exemplary trend of the change in partialrelaxation time as the state of health of the battery/cell degrades;

FIG. 14B illustrates actual measurements of the partial relaxation timeas the state of health of the battery/cell degrades with increasingnumber of charge/discharge cycle numbers (notably, each cycle is a fullcharge followed by a complete discharge);

FIG. 15A illustrates an exemplary embodiment of the overpotential of thebattery/cell wherein at the end of the “full” or “complete” relaxationtime of the battery/cell, the overpotential of the battery/cell may bedetermined; notably, the overpotential may be characterized as thevoltage difference between the terminal voltage of the battery/cell atthe initiation of the charge signal and the terminal voltage of thebattery/cell when the battery/cell is at full equilibrium (which may becharacterized as when the terminal voltage of the battery/cell issubstantially or relatively constant or unchanging under no chargingcurrent—which, for a conventional lithium ion battery/cell, is typicallyafter a temporal duration of, for example, 1 to 1,000 seconds);

FIG. 15B illustrates an exemplary charge signal (which may include aplurality of charge packets and/or discharge packets—each packet havingone or more charge pulses and/or one or more discharge pulses and anexemplary terminal voltage response of the battery/cell to such chargesignal wherein a first voltage (V₁) is identified (which correlates tothe voltage of the battery/cell at the end/termination of the chargesignal) at time T₁ and a second voltage (V₂) at time T₂ is identified(which correlates to a predetermined percentage of voltage V₁) whereinthe control circuitry may determine the overpotential or “full”relaxation time of the battery/cell based on or using the form, shapeand/or rate of decay of the terminal voltage; the predeterminedpercentage is preferably greater than 50% and, more preferably, between60% and 95%);

FIG. 15C illustrates an exemplary charge signal (which may include aplurality of charge packets and/or discharge packets—each packet havingone or more charge pulses and/or one or more discharge pulses and anexemplary terminal voltage response of the battery/cell to such chargesignal wherein a first voltage (V₁) is identified (which correlates oris related to the voltage of the battery/cell at thebeginning/initiation of the charge signal) at time T₁ and a secondvoltage (V₂) at time T₂ is identified (which correlates to apredetermined percentage of voltage V₁) wherein the control circuitrymay determine the overpotential or “full” relaxation time of thebattery/cell based on or using the form, shape and/or rate of decay ofthe terminal voltage; the predetermined percentage is preferably greaterthan 50% and, more preferably, between 60% and 95%);

FIG. 16 is a flowchart of an exemplary process of determining, adaptingand/or controlling the characteristics of a charging current based on orusing the overpotential or full relaxation time of the battery/cell inresponse to a charging signals (which may include one or more chargepackets/pulses and one or more discharge packets/pulses), according tocertain aspects of the present inventions; wherein the chargingtechniques and/or circuitry adapt, adjust and/or control one or morecharacteristics of the charge or current applied to or injected into thebattery/cell so that the overpotential or full relaxation time of thebattery/cell in response to one or more subsequent charging is less thana predetermined value and/or within a predetermined range duringsubsequent charging or recharging of the charge operation or cycle;

FIGS. 17A-17E illustrate, in flowchart like form, adaptive chargingtechniques having one or more adaption loops wherein each adaption loopestimates, calculates, measures and/or determines one or more differentparameters; notably, the adaptation loops may be implementedalone/separately or in combination; all combination or permutationsthereof are intended to fall within the scope of the present inventions;

FIGS. 18A-18D illustrate exemplary parameters of the adaption loopsincluding, for example, (i) a first adaption loop based on change interminal voltage in response to one or more charge/discharge pulses (ofone or more charge/discharge packets) and/or the partial relaxation timeof a pulse/packet, (ii) a second adaption loop based on SOC of thebattery/cell and/or full relaxation time or overpotential, (iii) a thirdadaption loop based on SOH (or changes therein) of the battery/cell, and(iv) a fourth adaption loop based on the temperature of the battery/cell(notably, in this embodiment, the system includes a temperature sensorto provide data which is representative of the temperature of thebattery/cell);

FIGS. 19A-19D illustrate exemplary charge pulses having different shapesand pulse widths; all combination or permutations of charge pulsecharacteristics are intended to fall within the scope of the presentinventions; and

FIGS. 20A-20D illustrate exemplary discharge pulses having differentshapes and pulse widths; all combination or permutations of dischargepulse characteristics are intended to fall within the scope of thepresent inventions.

Again, there are many inventions described and illustrated herein. Thepresent inventions are neither limited to any single aspect norembodiment thereof, nor to any combinations and/or permutations of suchaspects and/or embodiments. Each of the aspects of the presentinventions, and/or embodiments thereof, may be employed alone or incombination with one or more of the other aspects of the presentinventions and/or embodiments thereof. For the sake of brevity, many ofthose combinations and permutations are not discussed separately herein.

DETAILED DESCRIPTION

In a first aspect, the present inventions are directed to adaptivecharging techniques and/or circuitry for a battery/cell wherein thecharging techniques and/or circuitry adapt, adjust and/or control one ormore characteristics of the charge or current applied to or injectedinto the battery/cell so that the change in voltage at the terminals ofthe battery/cell (hereinafter “terminal voltage”) is within apredetermined range and/or below a predetermined value. For example,where the charging techniques and/or circuitry apply charge packets,having one or more charge pulses, to the battery/cell during a chargingsequence, cycle or operation, in one embodiment, the charging techniquesand/or circuitry may adapt, adjust and/or control the amplitude and/orpulse width of the charge or current pulses applied to or injected intothe battery/cell by subsequent packet(s) (for example, the immediatelysubsequent packets) so that the change in voltage at the terminals ofthe battery/cell in response to such subsequent charge packet(s) iswithin a predetermined range and/or below a predetermined value. In thisembodiment, the charging techniques and/or circuitry may adapt, adjustand/or control one or more characteristics of the charge or currentapplied to or injected into the battery/cell via adapting, adjustingand/or controlling the shape, amplitude and/or width of charge pulse(s)of the subsequent packet(s).

In another embodiment, the charging techniques and/or circuitry applycharge packets, having one or more charge pulses and one or moredischarge pulses, to the battery/cell during a charging sequence, cycleor operation. In this embodiment, the charging techniques and/orcircuitry may adapt, adjust and/or control one or more characteristicsof the charge or current applied to or injected into the battery/cell(via the charge pulses) and/or one or more characteristics of the chargeor current removed from the battery/cell (via the discharge pulses) sothat the change in terminal voltage in response to such charge orcurrent is within a predetermined range and/or below a predeterminedvalue during subsequent charging (for example, the immediatelysubsequent packets) of a charging sequence, cycle or operation. Forexample, the adaptive charging techniques and/or circuitry of thepresent inventions may adapt, adjust and/or control shape, amplitudeand/or width of charge pulse(s) and the shape, amplitude and/or width ofdischarge pulse(s) in a manner so that (i) a change in terminal voltageof the battery/cell due to the charge pulse(s) and (ii) a change interminal voltage of the battery/cell due to the discharge pulse(s) areeach within predetermined ranges during the charging sequence, cycle oroperation. In addition thereto, or in lieu thereof, the adaptivecharging techniques and/or circuitry of the present inventions mayadapt, adjust and/or control shape, amplitude and/or width of chargepulse(s) and discharge pulse(s) in a manner that provides a relationshipbetween (i) a change in terminal voltage of the battery/cell due to thecharge pulse(s) of a packet and (ii) a change in terminal voltage of thebattery/cell due to the discharge pulse(s) of the packet to be within apredetermined range during the charging sequence, cycle or operation.Thus, in those embodiments where the charge packet includes one or morecharge and discharge pulses, the charging techniques and/or circuitry ofthe present inventions may adapt, adjust and/or control one or morecharacteristics of the charge and/or discharge to control the change interminal voltage of the battery/cell in response to pulses so that (i)each such change is within predetermined range(s) and/or below apredetermined value(s), and/or (ii) the relationship between suchchanges is within a predetermined range and/or below a predeterminedvalue.

Notably, the charging techniques and/or circuitry may adapt, adjustand/or control the characteristics of the charge or current applied toor injected into the battery/cell based on or using an averaged responseof the battery/cell in connection with (i) a plurality of pulses in thepacket and/or (ii) a plurality of packets. For example, where thepackets include a plurality of charge pulses and/or a plurality ofdischarge pulses, the charging techniques and/or circuitry may employ anaveraged change in voltage in connection with the plurality of chargepulses and/or a plurality of discharge pulses. In this embodiment, thecharging techniques and/or circuitry of the present inventions mayadapt, adjust and/or control the characteristics of the charge anddischarge pulses applied to or injected into the battery/cell duringsubsequent packets based on or using an averaged response of thebattery/cell to plurality of charge pulses and/or a plurality ofdischarge pulses. Thus, in one embodiment, the charging techniquesand/or circuitry of the present inventions adapt, adjust and/or controlthe characteristics of one or more of the charge and/or discharge pulses(of subsequent packets) applied to the battery/cell based on or usingthe change in voltage at the terminals of the battery/cell averaged overa plurality of charge and/or discharge pulses of a preceding packet (forexample, the immediately preceding) is within a predetermined rangeand/or below a predetermined value.

In another embodiment, the charging techniques and/or circuitry of thepresent inventions may adapt, adjust and/or control the amount of chargeor current applied to or injected into the battery/cell by the packetsso that the change in voltage at the terminals of the battery/cellaveraged over a plurality of charge packet is within a predeterminedrange and/or below a predetermined value. Here, the charging techniquesand/or circuitry may adapt, adjust and/or control the characteristics ofthe charge applied to or injected into the battery/cell (via, forexample, adapting, adjusting and/or controlling the shape, amplitudeand/or width of charge pulse(s)) when an average change in voltage atthe terminals of the battery/cell in response to a plurality of chargepacket is outside a predetermined range.

The charging techniques and/or circuitry of the present inventions anyform of averaging. For example, the charging techniques and/or circuitryof the present inventions may average mutually exclusive groups ofpackets. Alternatively, the charging techniques and/or circuitry mayemploy a “rolling” average technique wherein the techniques and/orcircuitry determine or calculate a “new” average as a change in voltageat the terminals of the battery/cell, in response to a charge packet.

The adaptive charging techniques and/or circuitry of the presentinventions may intermittently, continuously and/or periodically adapt,adjust and/or control characteristics of the charge or current appliedto or injected into the battery/cell in connection with maintaining thechange in terminal voltage within a predetermined range. For example, inone embodiment, the adaptive charging techniques and/or circuitryintermittently, continuously and/or periodically measure or monitor theterminal voltage of the battery/cell (for example, measure or monitorthe terminal voltage of the battery/cell every Nth packet (where N=1 to10) and/or every 10-1000 ms). Based thereon or using such data, theadaptive charging techniques and/or circuitry may intermittently,continuously and/or periodically determine and/or adapt thecharacteristics of the charge or current injected into the battery/cell(or adapt the characteristics of the charge removed from thebattery/cell in those embodiments where a discharge current is employed)so that the change in terminal voltage is within a predetermined rangeand/or below a predetermined value (for example, determine and/or adaptthe characteristics of the charge or current injected into thebattery/cell every Nth packet (where N=1 to 10) and/or every 10-1000ms). In one embodiment, the adaptive charging techniques and/orcircuitry may intermittently, continuously and/or periodically determinethe terminal voltage of the battery/cell and, in response thereto orbased thereon, may intermittently, continuously and/or periodicallydetermine an amplitude and duration of subsequent charge pulses to beapplied to or injected into the battery/cell (which, in one embodiment,may be charge pulses of the immediately subsequent packet(s)) so thatthe change in terminal voltage of the battery/cell due to suchsubsequent charge pulses is within a predetermined range and/or below apredetermined value.

Thus, adaptive charging techniques and/or circuitry of the presentinventions may (i) measure or monitor the terminal voltage of thebattery/cell on an intermittent, continuous and/or periodic basis, (ii)determine whether a change in terminal voltage (which is response tocharge and discharge pulses) is within a predetermined range and/orbelow a predetermined value on an intermittent, continuous and/orperiodic basis, and/or (iii) adapt, adjust and/or controlcharacteristics of the charge or current signals applied to or injectedinto the battery/cell (for example, amplitude of the applied charge orcurrent) so that the change in terminal voltage is within apredetermined range and/or below a predetermined value on anintermittent, continuous and/or periodic basis. For example, adaptivecharging techniques and/or circuitry of the present inventions may (i)monitor, measure and/or determine the terminal voltage of thebattery/cell every X packets (where X=1 to 10), (ii) determine, every Ypackets (where Y=1 to 10), whether a change in terminal voltage (whichis in response to charge and discharge pulses) is within a predeterminedrange and/or below a predetermined value, and/or (iii) adapt, adjustand/or control characteristics of the charge or current signals appliedto or injected into the battery/cell, every Z packets (where Z=1 to 10),so that the change in terminal voltage is within a predetermined rangeand/or below a predetermined value. All permutations and combinationsare intended to fall within the scope of the present inventions. Indeed,such embodiments are applicable to the charging techniques and/orcircuitry which apply or inject (i) charge packets having one or morecharge pulses and (ii) charge packets having one or more charge pulsesand one or more discharge pulses.

Notably, the predetermined range may be fixed or may change, forexample, over time or use. The predetermined range may change based onone or more conditions or states of the battery/cell. In additionthereto, or in lieu thereof, the predetermined range may change based onone or more responses of the battery/cell to or during the chargingprocess.

In one embodiment, the predetermined range is based on empirical data,test data, simulation data, theoretical data and/or a mathematicalrelationship. For example, based on empirical data, the adaptivecharging techniques and/or circuitry associated with a givenbattery/cell (for example, a certain series, manufacturing lot,chemistry and/or design) may determine, calculate and/or employ apredetermined range as well as changes therein. Again, such changes may(i) in fixed, (ii) based on one or more conditions or states of thebattery/cell, and/or (iii) based on one or more responses of thebattery/cell to or during the charging process.

Thus, in one embodiment, the predetermined range may change based on,for example, a condition or state of the battery/cell and/or response ofthe battery/cell to the charging processes. For example, thepredetermined range may depend on one or more parameters of thebattery/cell including, for example, the state of charge (SOC) of thebattery, the state of health (SOH), overpotential or full relaxationtime (relative to full or complete equilibrium of the battery/cell)and/or relaxation time (to partial-equilibrium of the battery/cell).Here, the circuitry and/or techniques of the present inventions mayadjust, change and/or adapt the predetermined range employed todetermine whether a change in terminal voltage (which is response tocharge and/or discharge pulses) is within a predetermined range and/orbelow a predetermined value based on or using data which isrepresentative of the SOC of the battery/cell, the SOH of thebattery/cell, overpotential and/or relaxation time.

Notably, the SOC of a battery/cell, for example, a lithium-ionrechargeable battery/cell, is a parameter that is representative ofand/or indicates the level of electrical charge available in thebattery/cell. It may be characterized as a percentage of the nominalfull charge rating of the battery/cell, wherein a 100% SOC indicatesthat a battery/cell is fully charged and a zero reading indicates thatthe battery/cell is fully discharged. The SOH of a rechargeablebattery/cell (for example, a rechargeable lithium-ion battery/cell, is aparameter that describes, characterizes and/or is representative of the“age” of the battery/cell, the degradation levels of the battery/celland/or an ability of the battery/cell to hold charge, for example,relative to a given time in operation (for example, the initial time inoperation). The SOH of a battery/cell provides information to estimate,calculate, measure and/or determine other battery/cell parameters, forexample, the SOC and the voltage of the battery. Indeed, the terminalvoltage of the battery/cell changes as the SOH changes—and, hence thevoltage curves of the battery/cell tend to shift as the battery/cellages and as the battery/cell SOH deteriorates.

In one embodiment, based on or using initialization, characterizationand/or calibration data, the adaptive charging techniques and/orcircuitry of the present inventions may calculate or determine aninitial predetermined range or set of predetermined ranges for theparticular battery/cell. For example, in one embodiment, based on orusing (i) initialization, characterization and/or calibration data and(ii) empirical data, test data, simulation data, theoretical data and/ora mathematical relationship, the adaptive charging techniques and/orcircuitry of the present inventions may calculate or determine one ormore predetermined ranges for a particular or associated battery/cell.Indeed, in one embodiment, the adaptive charging techniques and/orcircuitry of the present inventions, based on or using (i)initialization, characterization and/or calibration data and (ii)empirical data, test data, simulation data, theoretical data and/or amathematical relationship, may calculate or determine a pattern orrelationship of the change of the predetermined range over time/use (forexample, (i) change based on one or more conditions or states of thebattery/cell, (ii) change based on one or more responses of thebattery/cell to or during the charging processes).

Determination or calculation of a predetermined range or set ofpredetermined ranges may also employ data which is representative of aseries, manufacturing lot, chemistry and/or design of the battery/cell.In one embodiment, based on empirical data, test data, simulation data,theoretical data and/or a mathematical relationship in conjunction withdata which is representative of a series, manufacturing lot, chemistryand/or design of the battery/cell, one or more predetermined rangestime/use may be determined or calculated. In addition, one or morechanges to such predetermined ranges (which may be based on one or moreconditions or states of the battery/cell and/or responses of thebattery/cell to or during the charging processes) may be determined orcalculated. In yet another embodiment, a predetermined range or set ofpredetermined ranges may be determined or calculated for a givenbattery/cell based on or using (i) the battery/cell response to aninitialization, characterization and/or calibration signals or sequence,and (ii) empirical data, which may, for example, be developed based on acertain series, manufacturing lot, chemistry and/or design. Notably,data which is representative of a predetermined range or set ofpredetermined ranges may be stored in memory, coupled to thebattery/cell, for use by the adaptive charging techniques and/orcircuitry of the present inventions.

As indicated above, in one embodiment, an initial predetermined range orset of predetermined ranges for a particular battery/cell may be basedon or using initialization, characterization or calibration data of thebattery/cell. The initialization, characterization and/or calibrationdata may be representative of the response of the battery/cell to acharacterization sequence. In one embodiment, the characterizationsequence may apply charge signals to the battery/cell. Thereafter, theadaptive charging techniques and/or circuitry may evaluate the responseto such signals by the battery/cell. Based thereon, the adaptivecharging techniques and/or circuitry may calculate or determinepredetermined ranges for the particular battery/cell. Suchinitialization, characterization or calibration data may be obtained,acquired and/or determined, for example, at manufacture, test orcalibration which may include the characterization sequence to obtain“unique” data regarding a given battery/cell.

Briefly, the initialization, characterization or calibration sequencesmay seek to establish values for certain of the predetermined limits andranges discussed herein. In one embodiment, the initialization,characterization or calibration sequences measure the change in terminalvoltage in response to charge and/or discharge packets (having chargeand/or discharge pulses) for new cells/batteries over the full range ofSOC. In a second embodiment, these values are used to cyclecells/batteries, and correlation data or tables are generated tocorrelate these change in terminal voltage with the capacity fade of thecells/batteries, and consequently with cycle life. Different values maybe used on different cells to create more complete correlationrelationships between changes in terminal voltage values or ranges andcapacity fade. Additionally, the change in terminal voltage values orranges may be correlated using physical models to the transport oflithium-ions, such as solving Fick's law and current transport lawwithin the battery/cell.

Notably, the predetermined range or ranges may be calculated ordetermined by the adaptive circuitry and/or processes of the presentinventions or by other circuitry and processes (for example, circuitrywhich is “off-device”, “off-chip” or separate from the circuitry of thepresent inventions). The predetermined range or ranges may be stored inmemory (for example, in a database or look-up table) during manufacture,test or calibration, and accessible to the adaptive circuitry and/orprocesses of the present inventions during operation.

As noted above, the predetermined ranges may change relative to initialpredetermined ranges in a predetermined manner (for example, in a fixedrelationship over time/use—which may be based on or using empiricaldata, test data, simulation data, theoretical data and/or a mathematicalrelationship). In addition thereto, or in lieu thereof, suchpredetermined ranges may depend on considerations such as the state orstatus of one or more parameters of the battery/cell including, forexample, the SOC, the SOH and/or temperature of the battery/cell.Notably, where one of such parameters is temperature, the system mayinclude a temperature sensor (thermally coupled to the battery/cell) toprovide data which is representative of the temperature of thebattery/cell.

For example, in one embodiment, the predetermined ranges depend on theSOC of the battery/cell. In this regard, the adaptive charging circuitryand techniques may apply or inject a higher current or charge into thebattery/cell when the SOC of the battery/cell is low and a lower currentor charge when the SOC of the battery/cell is high. Here, when anelectrical current charges a lithium-ion cell, lithium ions move fromthe cathode across the electrolyte and diffuse into the grains of theanode. Thus, at a low SOC, the diffusion rate of lithium ions into theanode can be faster than the diffusion rate at a high SOC. Thedifference in diffusion rate can vary substantially. Additionally, itmay be beneficial to use a higher charging current when the impedance(in particular, the real part thereof, which is representative of theresistance that the battery/cell exhibits to an applied electricalcurrent) is low and a lower charging current when the impedance is high.Therefore, in one embodiment, the adaptive charging algorithm ortechnique tailors, changes and/or adjusts the charging current tocontrol, manage and/or reduce the change in voltage in response to suchcharging current.

Notably, as the charging techniques and/or circuitry adapts, adjustsand/or controls one or more characteristics of the charge or currentapplied to or injected into the battery/cell so that the change interminal voltage in response to subsequent charging is within apredetermined range and/or below a predetermined value may impact thenet effective charge rate. That is, the net effective charge rate may beadjusted and/or controlled by way of adjusting and/or controlling one ormore characteristics of the charge or charging signal during a givencharging period including, for example, the amplitude of the currentcharge or charging signal, the shape of the charge or charging signal(for example, triangular, rectangular, sawtooth and/or square waves),the duration or width of the current charge or charging signal, thefrequency of the charge or charging signal and/or the duty cycle of thecharge or charging signal. However, the charging techniques and/orcircuitry may calculate, determine and/or estimate a peak amplitudeand/or duration of the current pulse(s) (for a given pulse shape—forexample, rectangular, triangle, sinusoidal or square current pulses) andresponsively control the charging to minimize and/or reduce the temporalduration of the overall charge sequence, cycle or operation. Indeed, thecharging techniques and/or circuitry may apply or inject less than amaximum charge (without the responsive terminal voltage of thebattery/cell attaining predetermined range) into the battery/cell duringone or more portions of the charging sequence, cycle or operation. Underthis circumstance, the temporal duration of the overall chargingsequence, cycle or operation may likely increase.

The predetermined range or ranges may be stored in permanent,semi-permanent or temporary memory. In this regard, the memory may storedata, equations, relationships, database and/or look-up table in apermanent, semi-permanent or temporary (for example, untilre-programmed) memory of any kind or type (for example, EEPROM, Flash,DRAM and/or SRAM). Moreover, the memory may be discrete or resident on(i.e., integrated in) other circuitry of the present inventions (forexample, control circuitry). In one embodiment, the memory may beone-time programmable, and/or the data, equations, relationships,database and/or look-up table of the predetermined range(s) may bestored in a one-time programmable memory (for example, programmed duringtest or at manufacture). In another embodiment, the memory is more thanone-time programmable and, as such, the predetermined range(s) may beupdated, written, re-written and/or modified after initial storage (forexample, after test and/or manufacture) via external or internalcircuitry.

It should be noted that, in certain embodiments, two considerations inconnection with implementing the adaptive charging circuitry andtechniques of the present inventions are to:

-   -   i. Minimize and/or reduce total charging time: For practical        reasons, the battery/cell is charged within a given period of        time (for example, a maximum allowed period of time). Typically,        a specification value is defined or chosen depending on the        application. For example, it is approximately 2 to 4 hours for        batteries employed in consumer applications, and for batteries        employed in transportation applications, it may be up to 8        hours. This results in a specification for a net effective        charging current; and    -   ii. Maximize and/or increase cycle life: To maximize and/or        increase cycle life of the battery/cell, it may be desirable to        charge the battery/cell (i) at a low current and/or (ii) provide        rest periods between or in periods of charging (for example,        between charging signals or packets) wherein no charge is        applied to or injected into the battery/cell.        Thus, in certain aspects, the charging circuitry of the present        inventions implement adaptive techniques which seek to (i)        minimize and/or reduce total charging time of the battery/cell        and (ii) maximize and/or increase the cycle life of the        battery/cell (by, for example, minimizing and/or reducing        degradation mechanisms of the charging operation).

With reference to FIG. 1A, in one exemplary embodiment, the adaptivecharging circuitry 10 for a battery/cell includes charging circuitry 12,monitoring circuitry 14 and control circuitry 16 which implements one ormore of the adaptive charging techniques described herein. Briefly, inone embodiment, charging circuitry 12 responsively applies one or morecurrent or charging signal to the battery/cell. (See, for example, FIGS.2A and 2B). The charging circuitry 12 may also apply one or morecharging signals (which provide a net input of charge or current intothe battery/cell) and one or more discharging signals (which provide anet removal of charge or current from the battery/cell). (See, forexample, FIGS. 2C and 2D).

The adaptive charging circuitry and techniques of the present inventionsmay employ any charging circuitry 12, whether described herein, nowknown or later developed, to charge the battery/cell; all such chargingcircuitry 12 are intended to fall within the scope of the presentinventions. For example, charging circuitry 12 of the present inventionsmay generate charging and discharging signals, packets and pulses (asdescribed herein). Notably, charging circuitry 12 is generallyresponsive to control signals from control circuitry 16.

Although discussed in more detail below, with reference to FIGS. 3A-3J,the charging and discharging signals may include a plurality of chargepackets wherein each charge packet includes one or more charge pulsesand, in certain embodiments, one or more discharge pulses. The chargingand discharging signals may also include one or more discharge packetswherein each discharge charge packet includes one or more dischargepulses. (See, FIGS. 3K-3N). Indeed, the charging and discharging signalsmay also include charge packets and one or more discharge packetswherein each charge packet and discharge packet includes one or morecharge pulses and/or one or more discharge pulses. (See, FIGS. 3K and3N).

With continued reference to FIG. 1A, monitoring circuitry 14 measures,monitors, senses, detects and/or samples, on an intermittent, continuousand/or periodic basis, condition or characteristics of the battery/cellincluding, for example, the terminal voltage, open circuit voltage (OCV)and/or temperature of the battery/cell. Notably, the adaptive chargingcircuitry and techniques of the present inventions may employ anymonitoring circuitry 14 and/or measuring or monitoring techniques,whether described herein, now known or later developed, to acquire suchdata; all such monitoring circuitry 14 and measuring or monitoringtechniques are intended to fall within the scope of the presentinventions. The monitoring circuitry 14 provides data which isrepresentative of the condition or characteristics of the battery/cellto control circuitry 16. Moreover, the monitoring circuitry may includeone or more temperature sensors (not illustrated) which is/are thermallycoupled to the battery/cell to generate, measure and/or provide datawhich is representative of the temperature of the battery/cell.

The control circuitry 16, using data from monitoring circuitry 14,calculates, determines and/or assesses the state or condition of thebattery/cell in connection with the charging or recharging process. Forexample, control circuitry 16 calculates, determines and/or estimates achange in terminal voltage of the battery/cell in response to charge orcurrent applied to or injected into the battery/cell. The controlcircuitry 16 may also calculate, determine and/or estimate one, some orall of the SOC of the battery/cell, SOH of the battery/cell, partialrelaxation time of the battery/cell and/or overpotential or fullrelaxation time of the battery/cell.

The control circuitry 16 also calculates, determines and/or implements acharging sequence or profile based on or using one or more of theadaptive charging techniques and algorithms described herein. In thisregard, control circuitry 16 adapts, adjusts and/or controls one or morecharacteristics of the charge or current applied to or injected into thebattery/cell (via controlling the operation of charging circuitry 12) sothat the change in terminal voltage of the battery/cell (in response tocharge or current applied to or injected into the battery/cell during acharging or recharging sequence/operation) is within a predeterminedrange and/or below a predetermined value. In one embodiment, wherecharging circuitry 12 applies charge packets (having one or more chargepulses) to the battery/cell, control circuitry 16 (implementing, forexample, one or more of the inventive adaptive charging techniquesdescribed herein) adapts, adjusts and/or controls the characteristics ofthe charge packets applied to or injected into the battery/cell (viacontrolling charging circuitry 12) so that the change in terminalvoltage of the battery/cell in response to each charge packet is withina predetermined range and/or below a predetermined value. For example,control circuitry 16 may instruct charging circuitry 12 to change thecharacteristics of the charge or current applied to or injected into thebattery/cell via controlling the shape, amplitude and/or width of chargepulse(s). In this way, control circuitry 16 may, in one embodiment,adapt, adjust and/or control the charge or current applied to orinjected into the battery/cell (via controlling charging circuitry 12)so that the change in terminal voltage of the battery/cell in responseto the charge or current is within a predetermined range and/or below apredetermined value.

In another embodiment, charging circuitry 12 applies charge packets,having one or more charge pulses and one or more discharge pulses, tothe battery/cell during a charging or recharging sequence, operation orcycle. In this embodiment, control circuitry 16 may adapt, adjust and/orcontrol (i) the characteristics of charge pulses applied and/or (ii) thecharacteristics of the discharge pulse so that the change in terminalvoltage is within a predetermined range and/or below a predeterminedvalue. Here again, control circuitry 16 (via control of chargingcircuitry 12) may adapt, adjust and/or control shape, amplitude and/orwidth of charge pulse(s) and the shape, amplitude and/or width ofdischarge pulse(s) in a manner so that (i) a change in terminal voltageof the battery/cell due to the charge pulse(s) and (ii) a change interminal voltage of the battery/cell due to the discharge pulse(s) areeach within predetermined ranges during the charging sequence. Inaddition thereto, or in lieu thereof, control circuitry 16 (via controlof charging circuitry 12) may adapt, adjust and/or control shape,amplitude and/or width of charge pulse(s) and discharge pulse(s) in amanner that provides a relationship between (i) a change in terminalvoltage of the battery/cell due to the charge pulse(s) and (ii) a changein terminal voltage of the battery/cell due to the discharge pulse(s) tobe within a predetermined range. Thus, in these embodiments, controlcircuitry 16 (implementing, for example, one or more of the inventiveadaptive charging techniques described herein) adapts, adjusts and/orcontrols one or more characteristics of the charge and/or dischargepulses so that changes in terminal voltage of the battery/cell inresponse to charge pulses and/or discharge pulses (i) is withinpredetermined range(s) and/or below a predetermined value(s) and/or (ii)the relationship between such changes is within a predetermined rangeand/or below a predetermined value.

Notably, control circuitry 16 may include one or more processors, one ormore state machines, one or more gate arrays, programmable gate arraysand/or field programmable gate arrays, and/or a combination thereof.Indeed, control circuitry and monitoring circuitry may share circuitrywith each other as well as with other elements; such circuitry may bedistributed among a plurality of integrated circuits which may alsoperform one or more other operations, which may be separate and distinctfrom that described herein. Moreover, control circuitry 16 may performor execute one or more applications, routines, programs and/or datastructures that implement particular methods, techniques, tasks oroperations described and illustrated herein. The functionality of theapplications, routines or programs may be combined or distributed. Inaddition, the applications, routines or programs may be implementing bycontrol circuitry 16 using any programming language whether now known orlater developed, including, for example, assembly, FORTRAN, C, C++, andBASIC, whether compiled or uncompiled code; all of which are intended tofall within the scope of the present inventions.

In operation, charging circuitry 12 applies a charge or current to thebattery/cell. (See, for example, the exemplary charge waveforms of FIGS.2A-2D). The monitoring circuitry 14 measures or detects voltages at theterminals of the battery/cell to determine a change in terminal voltagecaused by or as a result of the applied charge. In this regard, in oneembodiment, monitoring circuitry 14 measures the terminal voltage beforeapplying the charge or current to the battery/cell (for example,immediately before applying such charge or current) and at theconclusion thereof (for example, immediately after terminating theapplication of such charge or current. Control circuitry 16, using theterminal voltages measured by monitoring circuitry 14, calculates achange in the terminal voltage in response to such charge or current anddetermines whether the change in terminal voltage is within apredetermined range and/or below a predetermined value.

Where the change in terminal voltage is within a predetermined rangeand/or below a predetermined value, control circuitry 16, in oneembodiment, instructs charging circuitry 12 to apply the same or similarcharge packet to the battery/cell during subsequent charging. Where,however, the change in terminal voltage is outside the predeterminedrange (i.e., is less than or is greater than the predetermined range),control circuitry 16 adapts, adjusts and/or controls one or morecharacteristics of the charge or current applied to or injected into thebattery/cell (via charging circuitry 12) so that a change in voltage atthe terminals of the battery/cell in response to subsequent charging(for example, the immediately subsequent charge packet) is within thepredetermined range and/or below a predetermined value. Here, controlcircuitry 16 calculates or determines a change to one or morecharacteristics of the charging so that charge or current applied to orinjected into the battery/cell via subsequent charging is within apredetermined range and/or below a predetermined value. Notably, thepredetermined range may indeed change, for example, according to apredetermined rate or pattern, and/or according to the measured,determined and/or estimated SOC and/or SOH of the battery/cell.

In particular, with reference to FIGS. 1A, 4A and 5A, in one embodiment,monitoring circuitry 14 measures, samples and/or determines the terminalvoltage response to the charge pulse and provides data which isrepresentative of a first voltage (V₁), which correlates to a voltage ata beginning of the charge pulse, and a second voltage (V₂), whichcorrelates to a voltage at an end of the charge pulse and/or the peak ofthe change in the terminal voltage due to the charge pulse, to controlcircuitry 16. Based on or using such data, control circuitry 16calculates, determines and/or estimates whether the change in terminalvoltage, due to the charge pulse, is within a predetermined range and/orbelow a predetermined value. Where control circuitry 16 calculates,determines and/or estimates the change in terminal voltage is within apredetermined range and/or below a predetermined value, controlcircuitry 16 does not change and/or maintains the characteristics ofsubsequent charge packets due thereto (although control circuitry 16 mayindeed change such characteristics as a result of other considerations,such as, for example, considerations measurements of—relaxation time topartial equilibrium and/or SOC and/or SOH).

Where, however, control circuitry 16 determines the change in terminalvoltage is outside the predetermined range, control circuitry 16 maychange one or more characteristics of the charge packet including theshape, amplitude and/or width of charge pulse(s) in order to adapt,adjust and/or control the charge or current applied to or injected intothe battery/cell (via charging circuitry 12) so that a change in voltageat the terminals of the battery/cell in response to a subsequent chargeor current is within a predetermined range and/or below a predeterminedvalue. For example, where the change in terminal voltage in response toone or more charge packets is less than a predetermined range, controlcircuitry 16 may increase the amplitude and/or width of the chargepulse(s) to thereby inject more current or charge into the battery/cellin a subsequent packet (for example, the immediately subsequent packet).Alternatively, control circuitry 16 may increase the amplitude anddecrease the width of the charge pulse(s) to thereby inject the sameamount of current or charge into the battery/cell in a subsequent packet(for example, the immediately subsequent packet) but at a higheramplitude relative to the previous packet/pulse. (See, for example, FIG.6A).

Where, the change in terminal voltage in response to one or more chargepackets is greater than the predetermined range, control circuitry 16may decrease the amplitude and/or width of the charge pulse(s) tothereby inject less current or charge into the battery/cell in thesubsequent packet (for example, the immediately subsequent packet).Alternatively, control circuitry 16 may decrease the amplitude andincrease the width of the charge pulse(s) to thereby inject the sameamount of current or charge into the battery/cell in a subsequent packet(for example, the immediately subsequent packet) but at a loweramplitude relative to the previous pulse. (See, for example, FIG. 6A).

Notably, with reference to FIGS. 6A and 6B, in one embodiment, controlcircuitry 16 may adapt, adjust and/or control the amplitude and/orduration of the charge pulse as well as the duration of the rest period(T_(rest)). For example, in one embodiment, control circuitry 16, viacharging circuitry 12, adjusts the amplitude and duration of the chargepulse and the duration of the rest period (T_(rest)) to maintain aconstant period of the charge packet (T_(packet)). Alternatively,control circuitry 16 may adapt, adjust and/or control the duration ofthe rest period (T_(rest)) to accommodate other considerations andparameters in relation to the response of the battery/cell to charging(for example, overpotential or full relaxation time (relative to full orcomplete equilibrium of the battery/cell) and/or relaxation time (topartial-equilibrium of the battery/cell)).

In those embodiments where the charge packet includes one or more chargepulses and at least one discharge pulse, monitoring circuitry 14 maymeasure, sample and/or determine the terminal voltage of thebattery/cell in response to the charge and discharge pulses. Forexample, with reference to FIG. 5B, monitoring circuitry 14 may measure,sample and/or determine the terminal voltages responsive to the chargeand discharge pulses including (1) a first voltage (V₁), whichcorrelates to the voltage at a beginning of the charge pulse, (2) asecond voltage (V₂), which correlates to a voltage at an end of thecharge pulse and/or the peak of the change in the terminal voltage dueto the charge pulse, (3) a third voltage (V₃), which correlates to thevoltage at a beginning of the discharge pulse, and (4) a fourth voltage(V₄), which correlates to a voltage at an end of the discharge pulseand/or the peak of the change in the terminal voltage due to thedischarge pulse. The control circuitry 16, using the terminal voltageswhich are responsive to the charge and/or discharge pulses may calculateone or more changes in the terminal voltages of the battery/cell.

In one embodiment, control circuitry 16 employs the same techniques toadapt, adjust and/or control the charge as described above in connectionwith charge packets having no discharge pulses. That is, controlcircuitry 16 adjusts the characteristics of the charge pulse(s) tocontrol, adjust and/or provide a terminal voltage, in response to one ormore subsequent charge packets, which is within a predetermined rangeand/or below a predetermined value.

In another embodiment, control circuitry 16 calculates, determinesand/or estimates whether (i) a change in terminal voltage, due to thecharge pulse(s) and (ii) a change in terminal voltage of thebattery/cell due to the discharge pulse(s) are within the samepredetermined range or are each within respective predetermined rangesassociated with each of the pulse(s). Where the change in terminalvoltage, due to the charge pulse(s) and the change in terminal voltageof the battery/cell due to the discharge pulse(s) are outside the samepredetermined range or associated predetermined ranges, controlcircuitry 16 may adapt, adjust and/or control one or morecharacteristics of the charge pulse(s) and/or discharge pulse(s) (forexample, the shape, amplitude and/or width of charge pulse(s) and/ordischarge pulse(s)), via controlling charging circuitry 12, so that thechange in response to subsequent packet is within one or morepredetermined ranges and/or below one or more predetermined values. Thecontrol circuitry 16 may change the characteristics of the pulse(s)while maintaining an amount of current injected into the battery/celland/or an amount of charge or current removed from the battery/cellconstant or substantially constant relative to immediately subsequentpackets. Alternatively, control circuitry 16 may change thecharacteristics of the pulse(s) and change an amount of charge orcurrent applied to or injected into the battery/cell and/or an amount ofcharge or current removed from the battery/cell so that the change involtage in response to subsequent packet(s) is within one or morepredetermined ranges and/or below one or more predetermined values.

Thus, control circuitry 16 may adapt, adjust and/or control shape,amplitude and/or width of charge pulse(s) and the shape, amplitudeand/or width of discharge pulse(s) (via controlling charging circuitry12) in a manner so that (i) a change in terminal voltage of thebattery/cell due to the charge pulse(s) and/or (ii) a change in terminalvoltage of the battery/cell due to the discharge pulse(s) are eachwithin predetermined ranges during subsequent charging. In additionthereto, or in lieu thereof, control circuitry 16 of the presentinventions may adapt, adjust and/or control shape, amplitude and/orwidth of charge pulse(s) and discharge pulse(s) in a manner thatprovides a relationship between (i) a change in terminal voltage of thebattery/cell due to the charge pulse(s) and (ii) a change in terminalvoltage of the battery/cell due to the discharge pulse(s) to be within apredetermined range during subsequent charging. As such, in thoseembodiments where the charge packet includes one or more charge anddischarge pulses, control circuitry 16 of the present inventions mayadapt, adjust and/or control one or more characteristics of the chargeand/or discharge pulses of a packet to control the change in terminalvoltage of the battery/cell in response to charge pulse and/or dischargepulse so that (i) each such change is within predetermined range(s)and/or below predetermined value(s) and/or (ii) the relationship betweensuch changes is within a predetermined range and/or below apredetermined value.

With continued reference to FIG. 5B, control circuitry 16 may, inaddition to controlling the amplitude and width of the charge and/ordischarge pulses, may control the duration of one or both of the restperiods (T_(inter) and T_(rest)). In one embodiment, control circuitry16, via charging circuitry 12, adjusts the amplitude and width of thecharge and/or discharge pulses and duration of one or both of the restperiods (T_(inter) and T_(rest)) to maintain a constant period of thecharge packet (T_(packet)). Alternatively, control circuitry 16 mayadapt, adjust and/or control the amplitude and/or duration of the chargeand/or discharge pulses in relation to the change in terminal voltage ofthe battery/cell as well as adapt, adjust and/or control the duration ofone or both of the rest periods (T_(inter) and T_(rest)) to, forexample, accommodate other considerations and parameters in relation tothe response of the battery/cell to charging (for example, overpotentialor full relaxation time (relative to full or complete equilibrium of thebattery/cell) and/or relaxation time (to partial-equilibrium of thebattery/cell)).

As mentioned above, control circuitry 16 may adapt, adjust and/orcontrol the characteristics of subsequent charge or current applied toor injected into the battery/cell based on or using an averaged responseof the battery/cell in connection with a plurality of pulses in thepacket and/or a plurality of packets. For example, control circuitry 16may adapt, adjust and/or control the shape, amplitude and/or width ofcharge pulse(s) generated by charging circuitry 12 and applied to thebattery/cell by charge packets so that the change in voltage at theterminals of the battery/cell averaged over a plurality of charge packetis within a predetermined range and/or below a predetermined value.Similarly, the charging techniques and/or circuitry of the presentinventions may adapt, adjust and/or control the charge or currentapplied to or injected into the battery/cell by a plurality of chargepulses of a packet so that the change in voltage at the terminals of thebattery/cell averaged over a plurality of charge pulses of the packet iswithin a predetermined range and/or below a predetermined value.

The control circuitry 16 may employ any form of averaging now known orlater developed; all of which are intended to fall within the scope ofthe present inventions. For example, control circuitry 16 may employdiscrete or mutually exclusive groups of packets or “rolling” averageswherein the charging techniques and/or circuitry determine or calculatea “new” average as a change in voltage at the terminals of thebattery/cell, in response to a charge packet. Again, all forms ofaveraging and averaging techniques are intended to fall within the scopeof the present inventions.

Notably, the discussion with respect to the charge packets is applicableto control of the pulses of a discharge packet. In this regard, controlcircuitry 16 may adapt, adjust and/or control one or morecharacteristics of the discharge packets so that the change in voltageat the terminals of the battery/cell in response to a subsequentdischarge packet and/or charge packet is within a predetermined rangeand/or below a predetermined value. As mentioned above, the dischargepackets include one or more discharge pulses (see, for example, FIGS.3K-3N) as well as one or more charge pulses in addition to the dischargepulse(s) (see, for example, 3K, 3M and 3N).

In operation, similar to the charge packets, monitoring circuitry 14measures, samples and/or determines the terminal voltage of thebattery/cell in response to the discharge pulse and provides data whichis representative thereof to control circuitry 16, which determines thechange in voltage at the terminals of the battery/cell in response tothe discharge pulse. (See, for example, FIG. 5B). The control circuitry16 calculates or determines whether the change in voltage at theterminals of the battery/cell is within the predetermined range and/orbelow a predetermined value. Where the change in voltage is outside therange, control circuitry 16 may adapt, adjust and/or control one or morecharacteristics of the charge or current removed from the battery/cellby discharge packets so that the change in terminal voltage in responseto subsequent discharge packets (and/or subsequent charge packets) iswithin a predetermined range and/or below a predetermined value. (See,for example, FIG. 5B). Notably, control circuitry 16 may adapt, adjustand/or control the discharge packet (via control of charging circuitry12) in the same manner as that described above in connection with thecharge packet.

Notably, the predetermined range may be fixed or may change or beadjusted, for example, over time or use and/or based on one or moreconditions or states of the battery/cell and/or responses of thebattery/cell to or during charging. In one embodiment, the predeterminedrange is based on empirical data, test data, simulation data,theoretical data and/or a mathematical relationship. For example, basedon empirical data, control circuitry 16 associated with the battery/cellmay determine, calculate and/or employ predetermined ranges based on oneor more conditions or states of the battery/cell (for example, the SOCand/or SOH of the battery/cell) and/or responses of the battery/cell toor during charging. Such predetermined ranges fixed (for example,conform to a fixed or predetermined pattern) or may be variable.

In one embodiment, the changes in the predetermined range may be basedon one or more conditions or states of the battery/cell and/or responsesof the battery/cell to or during the charging process. For example, thepredetermined range may change and/or adapt based on or according to oneor more parameters of the battery/cell including, for example, the SOC,the SOH, overpotential or full relaxation time (relative to full orcomplete equilibrium of the battery/cell) and/or relaxation time (topartial-equilibrium of the battery/cell). Indeed, in one embodiment,where the battery/cell is a typical rechargeable lithium-ion (Li+)battery/cell employing a conventional chemistry, design and materials, apredetermined range may be dependent on the SOC of the battery/cell—forexample, the predetermined range may be (i) 250 mV±5% when thebattery/cell includes a SOC of between 0-10%, (ii) 235 mV±5% when thebattery/cell includes a SOC of between 10-20%, (iii) 215 mV±5% when thebattery/cell includes a SOC of between 20-30%, (iv) 190 mV±5% when thebattery/cell includes a SOC of between 30-50%, (v) 160 mV±5% when thebattery/cell includes a SOC of between 50-60%, (vi) 130 mV±5% when thebattery/cell includes a SOC of between 60-70%, (vii) 120 mV±5% when thebattery/cell includes a SOC of between 70-80%, (viii) 110 mV±5% when thebattery/cell includes a SOC of between 80-90%, (ix) 100 mV±5% when thebattery/cell includes a SOC of between 90-100%.

Indeed, in one exemplary embodiment, the net effective charging currentat 0-20% SOC may be 1-1.5 C, and at 80-100% SOC, it may be reduced to0.1-0.4 C. Notably, the taper of the change in net effective chargingcurrent over time may be linear or non-linear (for example, square rootof time). (See, for example, FIG. 7). It is also possible to make thenet effective charging current initially low for an SOC less than 10%,then make it reach a maximum around 5-20% SOC, then gradually make itdecline to a lower value near 90-100% SOC. All of these are variousembodiments of the taper function of the net effective charging currentwith the purpose of optimizing the charging current and charging timewhile taking into account the underlying physical mechanisms in thebattery, for example, mass transport of lithium ions, reaction kineticsand/or their associated time constants, and/or the strains in the anodeduring the intercalation of the lithium ions.

Thus, in one embodiment, control circuitry 16 may calculate, determineand/or employ one or more predetermined ranges based on the status orstate of the battery/cell (for example, based on or using data which isrepresentative of the SOC of the battery/cell, the SOH of thebattery/cell, overpotential and/or relaxation time). That is, thepredetermined range employed by control circuitry 16 and upon which thechange in terminal voltage is evaluated, may be dependent on status orstate of the battery/cell, for example, the SOC of the battery/cell andthe SOH of the battery/cell.

In one embodiment, based on or using initialization, characterizationand/or calibration data, control circuitry 16 or external circuitry maycalculate or determine an initial set of predetermined ranges for theparticular battery/cell. For example, in one embodiment, based on orusing (i) initialization, characterization and/or calibration data and(ii) empirical data, test data, simulation data, theoretical data and/ora mathematical relationship, control circuitry 16 or external circuitrymay calculate or determine a set of predetermined ranges for aparticular or associated battery/cell. Such predetermined ranges may bebased on one or more states of the battery/cell (for example, SOC of thebattery). The control circuitry may adaptively adjust the predeterminedranges over the life or use of the battery/cell—for example, based onthe changing conditions of the battery/cell (for example, a measured SOHof the battery/cell).

Notably, a set of predetermined ranges may be calculated or determinedby control circuitry 16 or by circuitry other than control circuitry 16(for example, circuitry which is “off-device” or “off-chip” relative tocontrol circuitry 16). The predetermined ranges may be stored in memory(for example, in a database or look-up table) during manufacture, testor calibration, and accessible to the adaptive circuitry and/orprocesses of the present inventions during operation.

In one embodiment, a set of predetermined ranges (based on, for example,SOC of the battery) may be calculated or determined and stored in memory(for example, during manufacture, test or calibration). Thereafter, thecontrol circuitry may adjust or adapt the set of predetermined rangesbased on the condition of the battery/cell—for example, the SOH of thebattery/cell. Alternatively, the memory may store multiple sets ofpredetermined ranges (for example, in a look-up table or matrix) andcontrol circuitry 16 employs a given predetermined range based on one ormore conditions of the battery/cell—including SOC and SOH of thebattery/cell. Thus, in this embodiment, the predetermined rangesemployed by control circuitry 16 depends on the SOH of the battery/cell,which designates or “identifies” a set of predetermined ranges, and theSOC of the battery/cell which designates or “identifies” the particularpredetermined range within the set of predetermined ranges. In theseembodiments, the control circuitry adapts the control of the chargingprocess based on or in response to a degrading SOH of the battery/cell.The set of predetermined ranges or the particular predetermined rangemay also be depend on other considerations such as the state or statusof other parameters of the battery/cell including, for example, theoverpotential, relaxation time and/or temperature of the battery/cell(for example, in one embodiment, the predetermined ranges may increasewith an increase in temperature of the battery/cell).

The predetermined ranges may be stored in any memory now known or laterdeveloped; all of which are intended to fall within the scope of thepresent inventions. For example, the memory may be a permanent,semi-permanent or temporary memory (for example, until re-programmed).In one embodiment, the memory may be one-time programmable, and/or thedata, equations, relationships, database and/or look-up table of thepredetermined range(s) may be stored in a one-time programmable memory(for example, programmed during test or at manufacture). In anotherembodiment, the memory is more than one-time programmable and, as such,the predetermined range(s) may be updated, written, re-written and/ormodified after initial storage (for example, after test and/ormanufacture) via external or internal circuitry.

With reference to FIGS. 1A-1C, memory 18 may be integrated or embeddedin other circuitry (for example, control circuitry 16) and/or discrete.The memory 18 may be of any kind or type (for example, EEPROM, Flash,DRAM and/or SRAM). The memory 18 may store data which is representativeof the predetermined ranges, equations, and relationships. Such data maybe contained in a database and/or look-up table.

As noted above, in certain embodiments, two considerations in connectionwith implementing the adaptive charging circuitry and techniques of thepresent inventions include (i) minimizing and/or reducing total chargingtime and (ii) maximizing and/or increasing cycle life. Under certaincircumstances, it is desirable to charge the battery/cell at the slowestpossible charge rate in order to extend its cycle life. For practicalreasons, however, the user may desire to charge the battery/cell withina given period of time (for example, a maximum allowed period of time).Typically, a specification value is defined, selected and/or chosendepending on the application of the battery/cell. For example, it isapproximately 2 to 4 hours for conventional batteries employed inconsumer applications, and for conventional batteries employed intransportation applications, it may be up to 8 hours. This results in aspecification for a net effective charging current. Moreover, tomaximize and/or increase cycle life of the battery/cell, it may bedesirable to charge the battery/cell (i) at a low current and/or (ii)provide relaxation or rest periods between charging periods. Thus, incertain aspects, the charging circuitry of the present inventionsimplement adaptive techniques which seek to (i) minimize and/or reducetotal charging time of the battery/cell and (ii) maximize and/orincrease the cycle life of the battery/cell (by, for example, minimizingand/or reducing degradation mechanisms of the charging operation).

In another aspect, the present inventions are directed to adaptivecharging techniques and/or circuitry employing data which is/arerepresentative of the relaxation time of the battery/cell to adapt,adjust and/or control one or more characteristics of the chargingprocess. In one embodiment, the adaptive charging techniques and/orcircuitry adapt, adjust and/or control one or more characteristics ofthe charge process to the relaxation time of the battery/cell. Inanother embodiment, the adaptive charging techniques and/or circuitrymay adapt, adjust and/or control a relaxation time of the battery/cellto, for example, maintain or provide a relaxation time that is within apredetermined range and/or less than a value or limit during at leastportions of the charging sequence, cycle or operation.

For example, where the charging techniques and/or circuitry apply chargepackets, having one or more charge pulses, to the battery/cell during acharging sequence, cycle or operation, in one embodiment, chargingtechniques and/or circuitry may adapt, adjust and/or control one or morecharacteristics of the charge packet to correlate a rest period of thecharge packet to a relaxation time of the battery/cell. In additionthereto, or in lieu thereof, the charging techniques and/or circuitrymay adapt, adjust and/or control one or more characteristics of thecharge packet to adapt, adjust and/or control a relaxation time of thebattery/cell, for example, to be within a predetermined range and/orless than a value or limit during the charging sequence, cycle oroperation. In these embodiments, the charging techniques and/orcircuitry may adapt, adjust and/or control one or more characteristicsof the charge packet via adapting, adjusting and/or controlling theshape, amplitude, temporal width of charge pulse(s) of the subsequentpacket(s), and/or the temporal width of one or more rest periods of thesubsequent packet(s).

In another embodiment, the charging techniques and/or circuitry applycharge packets, having one or more charge pulses and one or moredischarge pulses, to the battery/cell during a charging sequence, cycleor operation. Similar to the embodiments above, in this embodiment, thecharging techniques and/or circuitry may adapt, adjust and/or controlone or more characteristics of the charge pulse(s) and/or one or morecharacteristics of the discharge pulse(s) to adapt, adjust and/orcontrol one or more characteristics of the charge process in accordancewith or to correlate to the relaxation time of the battery/cell. Theadaptive charging techniques and/or circuitry may, in addition thereto,or in lieu thereof, adapt, adjust and/or control a relaxation time ofthe battery/cell to, for example, maintain or provide a relaxation timewithin a predetermined range and/or less than a value or limit duringthe charging sequence, cycle or operation. The charging techniquesand/or circuitry may implement these embodiments by adapting, adjustingand/or controlling one or more characteristics of the charge or currentapplied to, removed from the battery/cell and/or the rest periods—viaadapting, adjusting and/or controlling the shape, amplitude, temporalwidth of charge pulse(s) and/or discharge pulse(s) of the subsequentpacket(s), and/or the temporal width of one or more rest periods of thesubsequent packet(s).

The adaptive charging techniques and/or circuitry of the presentinventions may intermittently, continuously and/or periodically monitor,measure, determine and/or estimate the relaxation time of thebattery/cell (for example, monitor, measure, determine and/or estimatethe relaxation time of the battery/cell every Nth packet (where N=1 to10) and/or every 10-1000 ms). In addition thereto, the adaptive chargingtechniques and/or circuitry of the present inventions may alsointermittently, continuously and/or periodically use data which isrepresentative of the relaxation time of the battery/cell to adapt,adjust and/or control one or more characteristics of the chargingprocess (for example, adapt, adjust and/or control one or morecharacteristics of the charging process every Nth packet (where N=1 to10) and/or every 10-1000 ms). For example, in one embodiment, theadaptive charging techniques and/or circuitry intermittently,continuously and/or periodically monitor, measure, determine, estimatethe relaxation time of the battery/cell (which may change in accordancewith certain characteristics of the battery/cell—for example, SOC andSOH of the battery). Based on or using data which is representative ofthe relaxation time, the adaptive charging techniques and/or circuitrymay intermittently, continuously and/or periodically determine and/oradapt the characteristics of the charge or current injected into thebattery/cell (or adapt the characteristics of the charge removed fromthe battery/cell in those embodiments where a discharge current isemployed). In one embodiment, the adaptive charging techniques and/orcircuitry may intermittently, continuously and/or periodically determinethe relaxation time of the battery/cell and, in response thereto orbased thereon, may intermittently, continuously and/or periodicallydetermine an (i) amplitude and duration of subsequent charge pulses tobe applied to or injected into the battery/cell (which, in oneembodiment, may be charge pulses of the immediately subsequentpacket(s)) and/or (ii) a duration of a rest period. In this way, theduration of the rest period may correlate to the relaxation time and/orthe relaxation time is within a predetermined range and/or less than avalue or limit during subsequent charging.

Thus, adaptive charging techniques and/or circuitry of the presentinventions may (i) monitor, measure, determine and/or estimate therelaxation time of the battery/cell on an intermittent, continuousand/or periodic basis, (ii) determine whether the relaxation time iswithin a predetermined range and/or less than a value or limit on anintermittent, continuous and/or periodic basis, and/or (iii) adapt,adjust and/or control characteristics of the charge or current signals,on an intermittent, continuous and/or periodic basis, in accordance withor to correlate to the relaxation time of the battery/cell and/ormaintain or provide a relaxation time within a predetermined rangeand/or less than a value or limit during the charging. For example,adaptive charging techniques and/or circuitry of the present inventionsmay (i) monitor, measure, determine and/or estimate the relaxation timeof the battery/cell every X packets (where X=1 to 10), (ii) determinewhether the relaxation time is within a predetermined range and/or lessthan a value or limit every Y packets (where Y=1 to 10), and/or (iii)adapt, adjust and/or control characteristics of the charge or currentsignals, every Z packets (where Z=1 to 10). All permutations andcombinations are intended to fall within the scope of the presentinventions. Indeed, such embodiments are applicable to the chargingtechniques and/or circuitry which apply or inject (i) charge packetshaving one or more charge pulses and (ii) charge packets having one ormore charge pulses and one or more discharge pulses.

In another embodiment, the adaptive control circuitry and/or techniquesestimate, calculate, measure and/or determine the relaxation time(and/or changes therein) based on one or more events and/or chargingresponse characteristics (for example, the relaxation time of thebattery/cell is “inconsistent” with other data, characteristics orparameters of the battery/cell (for example, the SOC, the SOH,overpotential or full relaxation time and/or the voltage at theterminals of the battery/cell during charging). For example, in responseto detecting one or more events (due to, for example, an “inconsistency”between the battery/cell charge response characteristics or parameterswhich suggests, for example, the relaxation time may not be accuratelymeasured, estimated and/or determined), the adaptive control circuitryand/or techniques estimates, calculates, measures and/or determines therelaxation time (and/or changes therein) of a battery/cell and adapts,adjusts and/or controls the characteristics of the charge and/ordischarge signals based on or using relaxation time (and/or changestherein) of the battery/cell.

Notably, the predetermined ranges or values may be calculated ordetermined by the adaptive circuitry and/or processes of the presentinventions or by other circuitry and processes (for example, circuitrywhich is “off-device” or “off-chip”). The predetermined range or valuesmay be stored in memory (for example, in a database or look-up table)during manufacture, test or calibration, and accessible to the adaptivecircuitry and/or processes of the present inventions during operation.

The predetermined ranges or values may depend on considerations such asthe state or status of one or more parameters of the battery/cellincluding, for example, the SOC, the SOH and/or temperature of thebattery/cell. In one embodiment, due to the dependence of the relaxationtime on SOC, SOH and peak charging current, the adaptive chargingcircuitry and/or technique may charge the battery/cell at a highercurrent when the SOC of the battery/cell is low and at lower currentwhen the SOC of the battery/cell is high. For example, under certaincircumstances, at 80% SOC, the relaxation time difference between a peakcurrent of 2 C and 1 C is in excess of a factor of 20 (see, FIG. 8).When a current charges a lithium-ion battery/cell, lithium ions movefrom the cathode across the electrolyte and diffuse into the grains ofthe anode. At low SOC of the battery/cell, the diffusion rate of lithiumions into the anode may be faster than the diffusion rate at high SOC.The difference in diffusion rate may vary substantially. Notably, theimpact of temperature of the battery/cell on relaxation time may beincorporated into the set of predetermined ranges or values of theadaption process—and, as such, in one embodiment, where the controlcircuitry adapts such predetermined ranges or values based on or inaccordance with temperature of the battery/cell, temperature sensors(thermally coupled to the battery/cell) may or may not be employed.

Additionally, it may be beneficial to use a higher charging current whenthe impedance of the battery/cell is low and a lower charging currentwhen the impedance of the battery/cell is high. Therefore, in oneembodiment, the adaptive charging circuitry and techniques control,change and/or adjust the peak charging current to control, manage and/orreduce the relaxation time of the battery/cell in response thereto. Inthis way, the adaptive charging algorithm or technique implements acharging technique based on or in accordance with at least one of theconsiderations listed above, namely: (i) minimizing and/or reducingtotal charging time and (ii) maximizing and/or increasing cycle life.

Notably, as indicated above, the adaptive charging algorithm ortechnique may provide a net effective charging current for a lithium ionbattery/cell (employing a conventional chemistry, design and materials)at 0-20% SOC of, for example, 1-1.5 C, and at 80-100% SOC, a neteffective charging current of 0.1-0.4 C. The taper of the change in neteffective charging current over time may be linear or non-linear (forexample, square root of time). (See, for example, FIG. 7). All of theseare various embodiments of the taper function of the net effectivecharging current with the purpose of optimizing the charging current andcharging time while taking into account the underlying physicalmechanisms in the battery/cell are intended to fall within the scope ofthe present inventions, for example, the diffusion-limited relaxationtime, and/or the strains in the anode during the intercalation of thelithium ions.

With continued reference to FIG. 7, the taper shape, values andfunction, in certain embodiments, are driven or influenced by a desireto maintain the overpotential or full relaxation time below apredetermine limit and/or within predetermined values. The overpotentialor full relaxation time may be controlled by changing thecharacteristics of the current applied during the recharging operation(for example, the characteristics of the charge signals, dischargesignals, charge packets and discharge packets). As is discussed herein,the overpotential or full relaxation time limits/values are a functionof or varies in accordance with SOC and SOH and, as such, in oneembodiment, the charging current is a function of and varies inaccordance with SOC and SOH.

The predetermined ranges or values may be stored in permanent,semi-permanent or temporary memory. In this regard, the memory may storedata, equations, relationships, database and/or look-up table in apermanent, semi-permanent or temporary (for example, untilre-programmed) memory of any kind or type (for example, EEPROM, Flash,DRAM and/or SRAM). Moreover, the memory may be discrete or resident on(i.e., integrated in) other circuitry of the present inventions (forexample, control circuitry). In one embodiment, the memory may beone-time programmable, and/or the data, equations, relationships,database and/or look-up table of the predetermined range(s) may bestored in a one-time programmable memory (for example, programmed duringtest or at manufacture). In another embodiment, the memory is more thanone-time programmable and, as such, the predetermined ranges or valuesmay be updated, written, re-written and/or modified after initialstorage (for example, after test and/or manufacture) via external orinternal circuitry.

As mentioned above, in certain embodiments, the adaptive chargingcircuitry and/or technique may “balance” two considerations inconnection with implementing the present inventions including: (i)minimizing and/or reducing total charging time and (ii) maximizingand/or increasing cycle life. Thus, the charging circuitry of thepresent inventions may implement adaptive techniques which seek to (i)minimize and/or reduce total charging time of the battery/cell and (ii)maximize and/or increase the cycle life of the battery/cell (by, forexample, minimizing and/or reducing degradation mechanisms of thecharging operation).

Notably, the relaxation time of a battery/cell may be characterized as adecay of the terminal voltage, in response to the termination or removalof a current signal, from a peak terminal voltage to apseudo-equilibrium voltage level which is relatively constant andpreferably within 10% of peak deviation and, more preferably, within 5%of peak deviation. This relaxation time may be a characteristic of thelithium-ion battery/cell that, for current lithium-ion battery/celltechnology and chemistries, may vary from, for example, 20 ms to, forexample, several minutes. Notably, the terminal voltage of thebattery/cell may continue to decay to a full or complete relaxationwherein the voltage of the battery/cell is even more constant (whereinloss of charge is due to, for example, leakage current) and furtherdecay therefrom depends significantly on diffusion.

With reference to FIGS. 1A and 9A, in one embodiment, in operation,monitoring circuitry 14 measures or determines the terminal voltage ofthe battery/cell immediately prior to application of a charging currentpulse (identified as (V₁) in FIG. 9A). Upon termination of the secondcurrent pulse (in this exemplary embodiment), monitoring circuitry 14measures or determines when the terminal voltage of the battery/cell isat a predetermined value (for example, preferably less than 10% of peakdeviation and, more preferably, less than 5% of peak deviation)—(see V₅in FIG. 9A). In this exemplary embodiment, control circuitry 16calculates, estimates and/or determines the partial relaxation time (forexample, continuously, intermittently and/or periodically) based on theamount of time between (i) immediately after termination or applicationof the second charge pulse and (ii) when the terminal voltage is at apredetermined value. That is, in this embodiment, the partial relaxationtime may be characterized as difference between the time correspondingto immediately after termination of the second current pulse (T₁) andthe time when the terminal voltage is at a predetermined value (T₂).Thus, the partial relaxation time of the battery/cell may becharacterized as the decay time to the predetermined value (for example,preferably less than 10% of peak deviation and, more preferably, lessthan 5% of peak deviation).

With reference to FIG. 10A, in those instances where one or morecharacteristics of the charge pulse are not correlated to or with therelaxation time of the battery/cell, control circuitry 16 may adjustcharacteristics of subsequent charge current packet. For example, in oneembodiment, control circuitry 16 may adjust the characteristics ofsubsequent rest period (for example, rest period (T_(rest)) of thecharge packet—see FIG. 9A) so that a start of successive packetscorrelates to the relaxation time of the battery/cell (for example, arest period between successive pulses between successive packetsincludes a duration that is about equal to or greater than therelaxation time of the battery/cell). In another embodiment, controlcircuitry 16 may adapt, adjust and/or control one or morecharacteristics of the charge or discharge pulse(s) of the packet (forexample, the shape, peak amplitude, the pulse duration) to correlate tothe relaxation time of the battery/cell. In this way, control circuitry16 adjusts the duration of the rest period and/or the amplitude and/orduration of the charge/discharge pulses of subsequent packets tocorrelate to a measured relaxation time.

In another embodiment, in addition to the embodiment above, or in lieuthereof, control circuitry 16 (via charging circuitry 12) may adapt,adjust and/or control the relaxation time of the battery/cell to, forexample, maintain or provide a relaxation time that is within apredetermined range and/or less than a value or limit during thecharging operation. (See, FIG. 10B). In this embodiment, controlcircuitry 16 may adapt, adjust and/or control one or morecharacteristics of the charge pulse(s) subsequent packets to manage,maintain, control and/or adjust the relaxation time of the battery/cellto be within a predetermined range and/or less than a value or limit inresponse to a subsequent charge packet. For example, with reference toFIG. 9A, control circuitry 16 may adjust the pulse shape, pulseamplitude and/or pulse width of one or more of the charge pulses (of asubsequent charge packet), via control of charging circuitry 12, tomanage, maintain, control and/or adjust the relaxation time of thebattery/cell. In another embodiment, control circuitry 16 may adjust thewidth of the rest period (T_(inter)) between the pulses (of a subsequentcharge packet) to manage, maintain, control and/or adjust the relaxationtime of the battery/cell.

As indicated above, the relaxation time of the battery/cell may dependon the SOC of the battery/cell, the SOH of the battery/cell, peakcharging current and the temperature of the battery/cell. For example,when the SOC of the battery/cell is low and SOH of the battery/cell isrelatively healthy, the relaxation time of the battery/cell is shorterrelative to when the SOC of the battery/cell is high and SOH of thebattery/cell is relatively poor. As such, in one embodiment, thepredetermined range and/or value or limit of the relaxation time dependson or correlates to considerations such as the state or status of one ormore parameters of the battery/cell including, for example, the SOC, theSOH and/or temperature of the battery/cell. Due to the dependence of therelaxation time on SOC, SOH and peak charging current, control circuitry16, in one embodiment, may adjust the charging techniques according tothe SOC and SOH of the battery/cell, for example, charge thebattery/cell at: (i) a higher current and/or shorter relaxation timewhen the SOC of the battery/cell is low and/or the SOH of thebattery/cell is high, and (ii) a lower current and/or longer relaxationtime when the SOC of the battery/cell is high and/or the SOH of thebattery is low.

The predetermined ranges or values/limits of the relaxation time may becalculated or determined by control circuitry 16 or by other circuitryand processes (for example, circuitry which is “off-device” or“off-chip”). The predetermined range or values/limits may be stored inmemory (for example, in a database or look-up table) during manufacture,test or calibration, and accessible to control circuitry 16 duringoperation. The database or look-up table may correlate the relaxationtime to, among other things, the SOC, the SOH and/or temperature of thebattery/cell.

With reference to FIGS. 1A, 9B, 10A and 10B, in another exemplaryembodiment, the charge packet includes one or more charge and dischargepulses and control circuitry 16 calculates, estimates and/or determinesthe relaxation time (for example, continuously, intermittently and/orperiodically) in a similar manner. Here, monitoring circuitry 14measures or determines terminal voltage (V₁) of the battery/cellimmediately prior to application of a charge pulse. Upon termination ofthe discharge pulse (in this exemplary embodiment), monitoring circuitry14 measures or determines when the terminal voltage of the battery/cellis at a partial predetermined value—see V₅ in FIG. 9B. In this exemplaryembodiment, control circuitry 16 calculates, estimates and/or determinesthe partial relaxation time based on the amount of time between theimmediately after application of the discharge pulse and when theterminal voltage is at a predetermined value (for example, preferablyless than 10% of peak deviation and, more preferably, less than 5% ofpeak deviation). Here, the partial relaxation time may be characterizedas the temporal difference between the time corresponding to immediatelyafter terminating the discharge pulse (T₁) and the time when theterminal voltage is at a predetermined value (T₂). Again, the partialrelaxation time of the battery/cell may be characterized as the decaytime to the predetermined value.

Thus, control circuitry 16 may calculate, estimate and/or determine therelaxation time (for example, continuously, intermittently and/orperiodically). In response thereto, control circuitry 16 may adjustcharacteristics of subsequent charge current packet in accordance withor using data which is representative of the relaxation time. Forexample, with reference to FIG. 10A, in those instances where one ormore characteristics of the charge packet are not correlated to or withthe relaxation time of the battery/cell, control circuitry 16 may adjustcharacteristics of subsequent charge packet. In one embodiment, controlcircuitry 16 may adjust the characteristics of subsequent rest period(for example, rest period (T_(rest)) of the charge packet—see FIG. 9B)so that a start of successive packets correlates to the relaxation timeof the battery/cell (for example, a rest period between successivepulses between successive packets includes a duration that is aboutequal to or greater than the relaxation time of the battery/cell). Inanother embodiment, control circuitry 16 may adapt, adjust and/orcontrol one or more characteristics of the charge pulse and/or dischargepulse of the packet to correlate to a relaxation time of thebattery/cell. For example, in one embodiment, control circuitry 16 mayadjust the amplitude and duration of the discharge pulses so that therelaxation time is within a predetermined range and/or less than apredetermined value.

In addition to the embodiment above, or in lieu thereof, controlcircuitry 16 (via charging circuitry 12), may adapt, adjust and/orcontrol the relaxation time of the battery/cell to, for example,maintain or provide a relaxation time that is within a predeterminedrange and/or less than a value or limit during one or more portions (orall) of the charging operation. (See, FIG. 10B). In this embodiment,control circuitry 16 may adapt, adjust and/or control one or morecharacteristics of the charge pulse(s) subsequent packets to manage,maintain, control and/or adjust the relaxation time to be within apredetermined range and/or less than a value or limit in response to asubsequent charge packet. For example, with reference to FIG. 9B,control circuitry 16 may adjust the pulse amplitude and/or pulse widthof the charge pulse and/or discharge pulse (of a subsequent chargepacket), via control of charging circuitry 12, to manage, maintain,control and/or adjust the relaxation time of the battery/cell. Inaddition thereto, or in lieu thereof, in another embodiment, controlcircuitry 16 may adjust the width of the rest period (T_(inter)) betweenthe charge and discharge pulses (of a subsequent charge packet) tomanage, maintain, control and/or adjust the relaxation time of thebattery/cell. In this way, control circuitry 16 may manage or controlthe relaxation time of the battery/cell and thereby manage or controlthe time of the overall charging operation.

In addition thereto, in one embodiment, control circuitry 16 may adjustthe characteristics of the charge pulse and/or discharge pulse (forexample, amplitude and/or duration of such pulse(s)) to control oradjust the relaxation time as well as the rate, shape and/orcharacteristics of the decay of the terminal voltage of thebattery/cell. (See, for example, FIG. 9B). Here, control circuitry 16may adapt, adjust and/or control one or more characteristics of thecharge pulse and/or discharge pulse of the packet (via control ofcharging circuitry 12) to adjust or control “overshoot” or “undershoot”of the decay of the terminal voltage to partial equilibrium relative tothe predetermined value (for example, preferably less than 10% of peakdeviation and, more preferably, less than 5% of peak deviation).

For example, with reference to FIG. 11, control circuitry 16 may adapt,adjust and/or control the amplitude and pulse width of the dischargepulse to reduce or minimize the “overshoot” or “undershoot” of the decayof the terminal voltage of the battery/cell. In this regard, where thecharge process provides an “overshoot” of the decay of the terminalvoltage of the battery/cell relative to partial equilibrium (seedischarge pulse A), control circuitry 16 may instruct charging circuitry12 to adjust the characteristics of the discharge pulse and increase theamount of charge removed by the discharge pulse (for example, viaincreasing the amplitude and/or pulse width of the discharge pulse).Where, however, the charge process provides an “undershoot” of the decayof the terminal voltage of the battery/cell relative to partialequilibrium (see discharge pulse C), control circuitry 16 may instructcharging circuitry 12 to decrease the amount of charge removed by thedischarge pulse (for example, via decreasing the amplitude and/or pulsewidth of the discharge pulse). As such, control circuitry 16 may adjustthe characteristics of the discharge pulse of a subsequent charge packet(for example, the amplitude, pulse width and/or pulse shape) to controlor adjust rate, shape and/or characteristics of the decay of theterminal voltage of the battery/cell. (See, for example, FIG. 100). Inthis way, the relaxation time of the battery/cell, and the rate, shapeand/or characteristics of the decay of the terminal voltage of thebattery/cell, correlates to the characteristics of subsequent chargepackets and/or the is within a predetermined range and/or less than apredetermined value.

In addition thereto, or in lieu thereof, in one embodiment, controlcircuitry 16 may adjust the characteristics of the packet (for example,amplitude and/or duration of the charge pulses and/or discharge pulsesand/or the duration of the rest period) to control or adjust (i) therelaxation time of the battery/cell and (ii) the rate, shape and/orcharacteristics of the decay of the terminal voltage of thebattery/cell. (See, for example, FIGS. 9B, 10D and 11). Importantly, thepresent inventions are neither limited to any single aspect norembodiment thereof, nor to any combinations and/or permutations of suchaspects and/or embodiments. Moreover, each of the aspects of the presentinventions, and/or embodiments thereof, may be employed alone or incombination with one or more of the other aspects of the presentinventions and/or embodiments thereof.

Notably, in one embodiment, control circuitry 16 (implementing anadaptive charging algorithm) may evaluate relaxation time of thebattery/cell in response to different peak charging and dischargingcurrents (and/or pulse widths) to determine an optimal, suitable,predetermined and/or desired amount of time and rate, shape and/orcharacteristics of the decay of the terminal voltage of thebattery/cell. For example, control circuitry 16, via instructions tocharging circuitry 12, applies charge and/or discharge packets (havingdifferent attributes—for example, different amplitudes and/or pulsewidths of a trailing discharge pulse). The monitoring circuitry 14measures or monitors the response to such packets and control circuitry16 evaluates the relaxation time of the battery/cell, and/or the rate,shape and/or characteristics of the decay of the terminal voltage of thebattery/cell. In response, control circuitry 16 may instruct chargingcircuitry 12 to generate and apply charge and/or discharge packetshaving the appropriate characteristics. In addition thereto, or in lieuthereof, charging circuitry 12 may also select the characteristics ofthe packets from a look-up table that associates or correlates the peakcharging or discharging current with the SOC and SOH of thebattery/cell.

There are many techniques to control or adjust the partial relaxationtime—including, for example, controlling or adjusting thecharacteristics of the charge/discharge pulse packet as mentioned above(for example, the duration of the rest period(s) and/or the amplitude,shape and/or width of the pulses). Not all such techniques also minimizeor reduce the charge time of the charging process while simultaneouslyutilizing the maximum charge capacity of the cell/battery (in otherwords, using 100% depth of discharge of the cell/battery). Indeed, notall of these techniques minimize or reduce the charge time of thecharging process increase or maximize cycle life of the battery/cell.This notwithstanding, the present inventions are directed to all suchtechniques whether or not the techniques control or adjust relaxationtime to (i) increase or maximize cycle life of the battery and (ii)reduce or minimize the time of the charging or recharging process.

As noted above, control circuitry 16 may continuously, intermittentlyand/or periodically adapt, adjust and/or control one or morecharacteristics of the charge and/or discharge packet to adapt, adjustand/or control a relaxation time of the battery/cell, for example, to beless than a value or limit during charging. Here, control circuitry 16may continuously (for example, on a packet-by-packet basis),intermittently (which may be on an event basis—for example, therelaxation time of the battery/cell is “inconsistent” with other data,characteristics or parameters of the battery/cell (for example, the SOC,the SOH, overpotential or full relaxation time and/or the voltage at theterminals of the battery/cell during charging)) and/or periodically (ona number of packets basis and/or on a number of seconds or minutesbasis) adapt, adjust and/or control one or more characteristics of thepacket via adapting, adjusting and/or controlling the shape, amplitude,temporal width of the pulse(s) of the subsequent packet(s), and/or thetemporal width of one or more rest periods of the subsequent packet(s).

In addition thereto, or in lieu thereof, monitoring circuitry 14 andcontrol circuitry 16 may continuously, intermittently and/orperiodically measure and calculate a relaxation time of the battery/cellduring charging. Here, monitoring circuitry 14 measures and/or monitorsthe terminal voltage of the battery/cell (according to the variousembodiments herein) and, based thereon, control circuitry 16 calculatesand/or determines the relaxation time of the battery/cell.

Notably, control circuitry 16 may also calculate and/or determine theSOC and SOH of the battery/cell based on or using data which isrepresentative of the relaxation time of the battery/cell and/orterminal voltage (and/or change in terminal voltage in response tocharging). (See, the U.S. Provisional Patent Applications). For example,in the context of the SOC, as the battery/cell is charged, its SOCincreases. The control circuitry 16 detects, determines, calculatesand/or measures the SOC of the battery/cell, and, in response, controlcircuitry 16 (via implementation of the adaptive charging algorithm) mayadaptively increase the rest period of the packet to match or correlatethe rest period to the increasing relaxation time of the battery/cell.(See, for example, FIGS. 10E and 10F). In addition thereto, or in lieuthereof, control circuitry 16 may adaptively adjust (via controllingcharging circuitry 12) other characteristics of the packet (for example,the amplitude of the charge and/or discharge pulse, the duration orwidth of the pulses and/or shape of the pulses) to change, adjust,control and/or vary the relaxation time of the response of thebattery/cell to match or correlate the rest period to the increasingrelaxation time. For example, in one embodiment, control circuitry 16may adaptively increase the rest period to match the increasingrelaxation time, and may adaptively decrease the peak current of thecharge and/or discharge pulse.

Here, by decreasing the peak current of the charge signal, controlcircuitry 16 may decrease the relaxation time of the battery/cell.Alternatively, control circuitry 16 (via implementation of the adaptivecharging technique) may adaptively adjust the duty cycle of the chargesignal to increase the relaxation time of the battery/cell. Theresulting net effective charging current tends to have a peak when theSOC of the battery/cell is low (close to zero) and may graduallydecrease until it reaches its lowest value when the SOC of thebattery/cell is high (for example, above 80%). (See, for example, FIG.7). Notably, as mentioned above, the present inventions are neitherlimited to any single aspect nor embodiment thereof, nor to anycombinations and/or permutations of such aspects and/or embodiments.Moreover, each of the aspects of the present inventions, and/orembodiments thereof, may be employed alone or in combination with one ormore of the other aspects of the present inventions and/or embodimentsthereof. For example, in another aspect of the present inventions, thecontrol circuitry may adapt, adjust and/or control one or morecharacteristics of the charging process in accordance with or using (i)the change in terminal voltage of the battery/cell is within apredetermined range and (ii) the relaxation time of the battery/cell.(See, FIG. 12). In this embodiment, the control circuitry calculates anadjustment in one or more characteristics of a subsequent charge packet(for example, the amplitude and/or duration of a discharge pulse, and/orthe duration of a rest period) in accordance with or using (i) thechange in terminal voltage of the battery/cell in response to apreceding packet (as described in any of the embodiments set forthherein) and (ii) the relaxation time of the battery/cell (as describedin any of the embodiments set forth herein).

For example, where the relaxation time is not correlated to one or morecharacteristics of the charging process (for example, the relaxationtime is too long relative to the rest period) the control circuitrycalculates an adjustment in one or more characteristics of a subsequentcharge packet (for example, the amplitude and/or duration of a dischargepulse, and/or the duration of a rest period). The control circuitryimplements the adjustment, via control of the charging circuitry,provided such adjustment does not adversely impact change in terminalvoltage of the battery/cell (i.e., the change in terminal voltage of thebattery/cell is or remains within a predetermined range). In this way,the control circuitry, upon detecting (i) a change in terminal voltageof the battery/cell in response to a charge/discharge packet that isoutside a predetermined range and/or (ii) the relaxation time of thebattery/cell is outside a predetermined range and/or less than a valueor limit during the charging (for example), the charging circuitrycalculates and implements changes to one or more characteristics of thecharging process so that the change in voltage and the relaxation timeconstraints are satisfied.

As intimated above, the control circuitry may employ the data which isrepresentative of the terminal voltage of the battery/cell and/orrelaxation time of the battery/cell to obtain, measure, monitor,calculate, estimate the SOC of the battery/cell. In one embodiment, thecontrol circuitry calculates, estimates, measures and/or determines therelaxation time of the battery to one or more charge or discharge pulseand, based thereon, calculates, estimates and/or determines the SOC ofthe battery/cell. Here, the data which is representative of therelaxation time may correlate to the amount of charge added to thebattery/cell in response to the application of one or more chargingpulses, SOC of the battery/cell, and the temperature of thebattery/cell. Using data corresponding to or representative of therelaxation time for a given charge pulse or pulses, and temperature ofthe battery, circuitry (whether on-device or off-device) may derive,determine, calculate, generate and/or obtain the correlation of therelaxation time to the SOC of the battery/cell. In one embodiment, afunctional relationship or look-up table may be determined, calculated,generated and/or obtained which correlates a measured relaxation time tothe SOC of the battery/cell. The correlation of the relaxation time tothe SOC of the battery/cell (for example, the aforementionedrelationship or look-up table) may be employed by the control circuitry(and techniques implemented thereby) to, for example, adapt the chargeprofile of the battery/cell based on or using the SOC of thebattery/cell to, for example, alleviate, minimize and/or reduce theadverse impact of the charging operation on the SOH of the battery/celland increase, improve and/or maximize cycle life of the battery/cell.

In addition thereto, or in lieu thereof, the control circuitry maycalculate, estimate and/or determine the SOC of the battery/cell usingdata which is representative of the change in terminal voltage of thebattery/cell to one or more charge pulse. Using data corresponding to orrepresentative of the characteristics (for example, peak amplitude) ofthe voltage change (for example, increase) to one or more charge pulse,the control circuitry may derive, determine, calculate, generate and/orobtain the correlation of a peak amplitude of the voltage change to theSOC of the battery/cell. In one embodiment, a functional relationship orlook-up table may be determined, calculated, generated and/or obtainedwhich correlates a peak amplitude of the voltage change to the SOC ofthe battery/cell. The correlation of the peak amplitude of the voltagechange to the SOC of the battery/cell (for example, the aforementionedrelationship or look-up table may be employed to adapt the chargeoperation of the battery/cell based on or using the SOC of thebattery—for example, using the techniques described herein.

In one exemplary embodiment, circuitry and techniques of this aspect ofthe present inventions apply a charging current pulse with a finitecurrent and finite duration to the battery/cell. For example, theamplitude of the current pulse may be 0.5 C to 2 C, and the duration canvary from 10 ms to 500 ms. Indeed, such a charge pulse may be generatedvia a current source with temporal control over its output (e.g., aswitch). The charge pulse may be rectangular or of another shape. Thecurrent is measured over its duration, and the charge is computed byintegrating the current over that time duration. Notably C-rate is ameasure of the current rate through a battery/cell; that is, a 1 C is acurrent equivalent to dividing the charge capacity of the battery/cellby 1 hr. For example, 1 C is equivalent to 2.5 A for a 2.5 A.h.battery/cell; 0.5 C is equal to 1.25 A.

The terminal voltage of the battery/cell may be measured by monitoringcircuitry (for example, using a sampling period that is substantiallyshorter than the range of anticipated relaxation times of thebattery/cell—for example, the sampling period may be between 0.1 ms to1000 ms and preferably between 1 to 100 ms). In one embodiment, therelaxation time is measured by the difference between this relaxingvoltage and the terminal voltage of the battery/cell immediately priorto the application of the charging pulse (which is assumed to be whenthe cell is in partial equilibrium).

The relaxation time of the battery may be measured using any circuitryor technique now known or later developed, all of which are intended tofall within the scope of the present inventions. For example, in oneembodiment, the relaxation time may be measured when the relaxingvoltage difference drops below a predetermined threshold, for example 1mV. This threshold value may be higher and can vary from 0.1 mV to 20mV. In another possible approach, the slope of the voltage with time canbe computed, and compared to a threshold to estimate a relaxation time.In yet another approach, the relaxation time may be estimated ordetermined by observing the difference of voltage drop by a known ratio,such as 1/e. In yet another embodiment, the relaxation time is theamount of time for the battery to achieve equilibrium. All suchapproaches, and extensions of such approaches, serve to define a timeextent characterized by the decaying voltage curve which is relaxationtime.

The determination of the relaxation time as well as partial equilibriummay be absolute (a predetermined amount of voltage) or relative (forexample, within a predetermined percentage or range). Moreover, therelaxation time of the battery/cell may be based on one measurement—forexample, one charge pulse may be applied to the cell's terminal, and therelaxation time measured. The relaxation time may be based on aplurality of measurements—for example, the measurement may be repeatedseveral times (for example, sequentially) and thereafter themeasurements averaged. As such, the relaxation time may be based on anaverage of a plurality of measurements. Any form of averaging now knownor later developed; all of which are intended to fall within the scopeof the present inventions. For example, the control circuitry may employdiscrete or mutually exclusive groups of packets or “rolling” averages.Again, all forms of averaging and averaging techniques are intended tofall within the scope of the present inventions.

Notably, the measurement of the relaxation time may be performedintermittently (for example, in response to a change in operatingconditions (for example, temperature), periodically or continuously. Forexample, the measurement of the relaxation time may be performed atregular time intervals to correspondingly determine the SOC of thebattery/cell. These intervals may vary from one second to one or moreminutes. Additionally, the SOC of the battery/cell may be determined atany time—for example, during normal operation (in situ) or duringcharging operation. Indeed, since the duration of the measurement isrelatively short (ranging from tens of milliseconds to a few seconds),the system may determine, calculate, estimate and/or obtain therelaxation time of the battery (which may be correlated to the SOC ofthe battery) during normal operation without disrupting the normaloperation of the cell. For example, where the battery/cell isincorporated into a laptop computer, the main processor may choose toinsert these measurements at moments it deems the laptop to be in idleor near idle.

As noted above, in another embodiment, measurements of the relaxationtime may be performed while the battery/cell is either being charged orbeing discharged. In a charging configuration, the charging may beinterrupted for a few seconds to allow the battery/cell to relax to anequilibrium voltage, then the charging pulse is applied, and therelaxation time is subsequently measured. A similar approach is appliedif the battery/cell is discharging.

In addition to determining the SOC of the battery/cell based on or usingrelaxation time measurements, or in lieu thereof, the monitoringcircuitry may also measure data which is representative of thecharacteristics (for example, peak amplitude) of the voltage increase toone or more charge pulse and, based thereon, the control circuitry maydetermine the SOC of the battery/cell. For example, the peak voltagerise which is responsive to the application of a current pulse of finiteduration may be employed as an additional or alternate measure of SOC.The peak voltage of the battery/cell in response to a charge pulse maybe dependent on the SOC of the battery/cell (See, FIGS. 13A and 13B).

Notably, all of the exemplary embodiments discussed herein in connectionwith relaxation time are entirely applicable to determining the SOCbased on or using data which is representative of the characteristics(for example, peak amplitude) of the voltage change (for example,increase) to one or more charge pulse. For example, the measurement ofthe characteristics (for example, peak amplitude) of the voltageincrease to one or more charge pulse may be performed intermittently(for example, in response to a change in operating conditions (forexample, temperature), periodically or continuously. Moreover, the peakamplitude measurement may be based on one or more measurement—forexample, one charge pulse may be applied to the cell's terminal, and thepeak amplitude measured. The measurement may be repeated several timessequentially and thereafter the measurements averaged. Thus, for thesake of brevity, such exemplary embodiments in the context ofdetermining the SOC based on or using data which is representative ofthe characteristics (for example, peak amplitude) of the voltage change(for example, increase) to one or more charge pulse will not berepeated.

Further, using data of the characteristics of the voltage change (forexample, increase in peak amplitude) to one or more charge pulse, thecircuitry and techniques of this aspect of the inventions may derive,determine, calculate, generate and/or obtain a correlation of thevoltage change to the SOC of the battery. In one embodiment, afunctional relationship or look-up table may be determined, calculated,generated and/or obtained which correlates a measured peak amplitude tothe SOC of the battery/cell. The correlation of the voltage change tothe SOC of the battery/cell (for example, the aforementionedrelationship or look-up table) may be employed by circuitry and/ortechniques of the present inventions to adapt the charging profile ofthe battery/cell based on or using the SOC of the battery/cell to, forexample, alleviate, minimize and/or reduce the adverse impact of thecharging operation on the state of the health of the battery andincrease, improve and/or maximize cycle life of the battery/cells.

Notably, all of these embodiments may be thought of as variousimplementations of pinging or interrogating the battery/cell with ashort current pulse of known current and duration, and monitoring thecell's signature voltage (akin listening to its echo). The voltagesignature has a peak voltage signature and a decay time constant, bothcharacteristically dependent on SOC, and hence can be used independentlyor jointly to measure SOC of the battery/cell.

Moreover, the current pulse of the charge and/or discharge packets mayalso be employed ping or interrogate the battery with a short currentpulse of known current and duration, and monitoring the terminal voltageof the battery/cell). Again, the voltage signature has a peak voltagesignature and a decay time constant, both characteristically dependenton SOC, and hence may be used independently or jointly to measure,determine and/or estimate SOC.

As mentioned herein, the relaxation time and/or the change in terminalvoltage of the battery/cell may depend on the SOH of the battery/cell.The present inventions may employ any technique and/or circuitry,whether now known or later developed, to estimate, calculate, measureand/or determine the SOH (and/or changes therein) of abattery/cell—including the techniques and/or circuitry described herein.(See, FIGS. 1A-1C). In one embodiment, the circuitry and techniques mayestimate, calculate, measure and/or determine the SOH of thebattery/cell using or based on a relaxation time or relaxation timeconstant. Briefly, in operation, such circuitry and techniques apply acharging and/or discharging signal(s) (for example, of short duration)to the battery/cell. The circuitry and techniques measure, assess and/orsample the voltage at the terminals of the battery/cell to estimate,calculate, measure and/or determine the relaxation time. Using or basedon the relaxation time (which may be is a direct measure of the carrier(ion) transport dynamics between the two electrodes of the battery), thecircuitry and techniques estimate, calculate, measure and/or determinethe SOH of the battery/cell.

In one embodiment, the circuitry and techniques estimate, calculate,measure and/or determine the SOH by injecting or applying an electricalcharge signal into the battery/cell. An electrical current signal isapplied to the cell's terminals for a known duration of time, forexample, ranging from a few milliseconds to several seconds. The signalis then interrupted and the voltage across the battery's terminals ismeasured. The voltage decays to a partial-equilibrium value which may be0.1-10% of the peak voltage deviation reached during the chargesignal—and preferably, 0.1-5% of the peak voltage deviation reachedduring the charge signal. The time required to reach thispartial-equilibrium value is a relaxation time that depends on the SOHof the battery/cell (FIGS. 9A-9C). This relaxation time is relativelyshort when the battery/cell is “new” and increases as the battery/cellages and the transport dynamics of the ions within the battery degrade.

Notably, peak voltage deviation, in this context, is relative to theterminal voltage of the battery/cell when the current of thecharge/discharge packet is first or initially applied. (See, V₁, forexample, in FIGS. 5A, 5B and 9A-9C).

In another embodiment, the circuitry and techniques estimate, calculate,measure and/or determine the SOH of a battery/cell by initiallyinjecting or applying the charging signal described above for a shortduration (for example, for a period of between 1 ms and 50 ms), and thenapplying a discharging signal of a duration (for example, for a periodof between 5 ms and 100 ms). The voltage across the battery's terminalsgradually returns to its partial-equilibrium (for example, 0.1-10% ofthe peak voltage deviation reached during the discharge signal—andpreferably, 0.1-5% of the peak voltage deviation reached during thedischarge signal). In this particular embodiment, we are interested inor focus on the second relaxation period as shown in FIGS. 9B and 9C.

Notably, as the battery/cell ages, for example, as it is repeatedlycharged and discharged during use or operation, the SOH of thebattery/cell deteriorates and its capacity to store charge decreases orfades. The relaxation time also changes and that change is arepresentative of the SOH of the battery/cell (FIG. 14A). The relaxationtime needed to reach the partial-equilibrium value lengthensconsiderably. Alternatively, the voltage deviation for a particularpoint in time increases as the SOH of the battery/cell degrades. Forexample, as shown in FIG. 14A, points R1, R2 and R3 all occur at thesame time value, with R1 corresponding to a new battery. As the SOH ofthe battery degrades or worsens, the voltage deviation increases asrepresented by points R2 and R3. FIG. 14B shows measurement of suchvoltage deviation after an increasing number of charge-discharge cyclesthat are known to degrade the SOH of the battery/cell.

In yet another embodiment, the circuitry and techniques estimate,calculate, measure and/or determine the SOH assessing, determiningand/or measuring the deviation of the voltages at the terminals of thebattery/cell from a true or full equilibrium voltage during charging.Here, during charging, the voltage at the terminals rises to a valuethat may be, for example, 10 mV to 100 mV higher than the battery's fullequilibrium resting voltage. This exemplary difference is noted as theoverpotential of the battery (FIG. 15A). During the charging process,the charging current is interrupted and the voltage returns to its trueequilibrium voltage. The overpotential or full relaxation time may becharacterized and/or measured as the difference in terminal voltageafter the charging current is interrupted and a second measurement whenthe voltage at the terminals is deemed to be unchanging or substantiallyconstant—typically after a duration of, for example, about 1 to 1,000seconds. Alternatively, the overpotential may be characterized as thedifference in (i) the potential after a first relaxation period (withthe cell reaching a partial-equilibrium point) or potential immediatelybefore application of a charging signal or at the beginning of theapplication of the charging signal and (ii) the potential at the trueequilibrium voltage of the battery/cell, when the terminal voltage ofthe battery/cell is relatively or substantially constant or unchangingunder no charging current) (FIG. 15A). In either case, thisoverpotential value increases as the SOH degrades (capacity fade of thebattery/cell), and is directly correlated to SOH of the battery/cell.

In yet another aspect, the SOH may be employed to improve the accuracyin estimating the SOC of the battery/cell, which may be a measure orestimate of the available discharge capacity (for example, in connectionwith a gauge, indicator and/or information which is representative of anavailable energy capacity of the battery/cell), and/or to improve safetyin connection with, for example, charging or recharging a battery/cell.In this regard, as the battery/cell ages, for example as it isrepeatedly charged and discharged during use or operation, the SOH ofthe battery/cell deteriorates and its capacity to store charge decreasesor fades. In this aspect, the circuitry and techniques employ the SOH tocompensate the data (for example, the SOC of the battery/cell) which maybe employed in connection with a gauge, indicator and/or informationwhich is representative of an available energy capacity of thebattery/cell. In this way, such a gauge, indicator and/or informationprovides a more accurate representation of the available energy capacityof the battery/cell. Thus, in this embodiment, the circuitry andtechniques which measure or estimate the available discharge capacity ofthe battery/cell adjust or compensate information which isrepresentative of an available energy capacity of the battery/cell usingthe SOH of the battery/cell.

In yet another aspect, the adaptive charging techniques and/or circuitryof the present inventions may measure, monitor and/or determine theoverpotential or full relaxation time of the battery/cell and, inresponse thereto, adapt, adjust and/or control one or morecharacteristics of the charge or current applied to or injected into thebattery/cell so that the overpotential or full relaxation time is belowa predetermined value and/or within a predetermined range and/or thefull relaxation time is less than a predetermined value and/or within apredetermined range. The overpotential or full relaxation time may becharacterized and/or measured as the difference in terminal voltage ofthe battery/cell after the charging current is interrupted and a secondmeasurement when the voltage at the terminals is essentially, relativelyor deemed to be unchanging—typically (for a conventional lithium ionbattery/cell) after a duration lasting, for example, about 1 to 1,000seconds. Alternatively, the overpotential may be characterized as thedifference in terminal voltage after a first relaxation period (with thecell reaching a partial-equilibrium point) and the potential at the fullequilibrium voltage of the battery/cell (FIG. 15A).

For example, where the adaptive charging techniques and/or circuitrydetermine the overpotential or full relaxation time of the battery/cellexceeds the predetermined range (via measuring or monitoring theterminal voltage), the amount of current applied to the battery/cellduring the charging process may be adapted, adjusted and/or controlledso that, in response to subsequent charging signals, the terminalvoltage of the battery/cell is below a predetermined value and/or doesnot exceed the predetermined range. In one embodiment, where theadaptive charging techniques and/or circuitry determine theoverpotential or full relaxation time of the battery/cell exceeds theupper value of the predetermined range, the adaptive charging techniquesand/or circuitry may reduce the average current applied or input intothe battery/cell during the charging process. For example, in oneembodiment, the adaptive charging techniques and/or circuitry may reducethe peak current of the packet applied or input into the battery/cellduring the charging process. Alternatively, the adaptive chargingtechniques and/or circuitry may decrease the duty cycle of the pulseswithin a packet to decrease the amount of charge applied to thebattery/cell. Where, however, the overpotential or full relaxation timeof the battery/cell is less than the lower value of the predeterminedrange, the adaptive charging techniques and/or circuitry may increasethe amount of current applied or input into the battery/cell during thecharging process. Alternatively, the adaptive charging techniques and/orcircuitry may increase the duty cycle within a packet to increase theamount of charge applied into the battery/cell.

In one embodiment, the adaptive charging techniques and/or circuitry ofthe present inventions intermittently, continuously and/or periodicallydetermine, measure and/or monitor the overpotential or full relaxationtime of the battery/cell less frequently relative to the measuring ormonitoring the terminal voltage to assess, determine and/or monitor theterminal voltage difference in connection with or in response to acharge and/or discharge packet (as discussed above). For example, theadaptive charging techniques and/or circuitry of the present inventionsmay intermittently, continuously and/or periodically determine, measureand/or monitor the overpotential or full relaxation time of thebattery/cell (for example, determine, measure and/or monitor theterminal voltage of the battery/cell every Nth packet (where N=1,000 to10,000) and/or every 1-1000 seconds). Based thereon or using such data,the adaptive charging techniques and/or circuitry may intermittently,continuously and/or periodically determine and/or adapt thecharacteristics of the charge or current injected into the battery/cell(or adapt the characteristics of the charge removed from thebattery/cell in those embodiments where a discharge current is employed)so that the overpotential or full relaxation time of the battery/cell iswithin a predetermined range or below a predetermined value (forexample, determine and/or adapt the characteristics of the charge orcurrent injected into the battery/cell every Nth packet (where N=1,000to 10,000) and/or every 1-1000 seconds based on considerations ofoverpotential or full relaxation time). In one embodiment, the adaptivecharging techniques and/or circuitry may intermittently, continuouslyand/or periodically determine, measure and/or monitor the overpotentialor full relaxation time of the battery/cell (for example, via measuringor monitoring terminal voltage of the battery/cell) and, in responsethereto or based thereon, may intermittently, continuously and/orperiodically determine an adjust, control or adapt the amount of currentor charge applied to or injected into the battery/cell (which, in oneembodiment, may be charge pulses of the immediately subsequent packet(s)of the immediately subsequent charge signals) so that the overpotentialor full relaxation time of the battery/cell due to such subsequentcharging is within a predetermined range.

Thus, adaptive charging techniques and/or circuitry of the presentinventions may (i) determine, measure and/or monitor the overpotential(via measuring or monitoring the terminal voltage) of the battery/cellon an intermittent, continuous and/or periodic basis, (ii) determinewhether the overpotential is below a predetermined value and/or within apredetermined range on an intermittent, continuous and/or periodicbasis, and/or (iii) adapt, adjust and/or control characteristics of thecharge or current signals applied to or injected into the battery/cell(for example, amount of the applied charge or current) so that theoverpotential of the battery/cell to such charging is below apredetermined value and/or within a predetermined range on anintermittent, continuous and/or periodic basis. For example, adaptivecharging techniques and/or circuitry of the present inventions may (i)determine, measure and/or monitor the terminal voltage of thebattery/cell every X packets (where X=100 to 10,000) and/or every 1-1000seconds, (ii) determine, every Y packets (where X=100 to 10,000) and/orevery 1-1000 seconds, whether the overpotential (which is response tocharge and discharge signals) is within a predetermined range, and/or(iii) adapt, adjust and/or control characteristics of the charge orcurrent signals applied to or injected into the battery/cell, every Zpackets (where X=100 to 10,000) and/or every 1-1000 seconds, so that theoverpotential is within a predetermined range. All permutations andcombinations are intended to fall within the scope of the presentinventions. Indeed, such embodiments are applicable to the chargingtechniques and/or circuitry which apply or inject (i) charge packetshaving one or more charge pulses and (ii) charge packets having one ormore charge pulses and one or more discharge pulses.

Notably, although the discussion below refers to overpotential, thatdiscussion is applicable to full relaxation time of the battery/cell inaddition to overpotential. As such, the adaptive charging techniquesand/or circuitry of the present inventions may (i) determine, measureand/or monitor the full relaxation time (via measuring or monitoring theterminal voltage) of the battery/cell on an intermittent, continuousand/or periodic basis, (ii) determine whether the full relaxation timeis below a predetermined value and/or within a predetermined range on anintermittent, continuous and/or periodic basis, and/or (iii) adapt,adjust and/or control characteristics of the charge or current signalsapplied to or injected into the battery/cell (for example, amount of theapplied charge or current) so that the full relaxation time of thebattery/cell to such charging is below a predetermined value and/orwithin a predetermined range on an intermittent, continuous and/orperiodic basis. For the sake of brevity, that discussion will not berepeated in connection with full relaxation time.

The monitoring circuitry and/or control circuitry may determine, measureand/or monitor the overpotential of the battery/cell using any techniqueand/or circuitry now known or later developed. For example, in oneembodiment, the monitoring circuitry measures, samples and/or monitorsthe terminal voltage of the battery/cell immediately before applicationof a charging signal or at the beginning of the application of thecharging signal. Once the battery/cell reaches full equilibrium (whichmay be characterized as when the terminal voltage of the battery/cell isrelatively constant or unchanging when no charging signal is applied),the monitoring circuitry measures, samples and/or monitors the terminalvoltage of the battery/cell. The control circuitry may determine ormeasure the overpotential of the battery/cell as the difference betweenthese two terminal voltages.

In addition thereto or in lieu thereof, the adaptive charging techniquesand/or circuitry of the present inventions may determine, measure and/ormonitor the overpotential of the battery/cell by measuring, samplingand/or monitoring the terminal voltage of the battery/cell aftertermination of a charging signal and, based on or using thecharacteristics of the decay of the terminal voltage after terminatingthe charging signal, the control circuitry may derive, calculate,estimate, and/or determine the overpotential. For example, the controlcircuitry may determine the overpotential by extrapolating from theterminal voltage of the battery/cell after termination of a chargingsignal and the characteristics of the decay of the terminal voltage. Inone embodiment, the monitoring circuitry may measure, sample and/ormonitor an “initial” terminal voltage of the battery/cell afterterminating the charging signal (for example, immediately orsubstantially immediately after terminating the charge signal) and,based on the amount of time required for the terminal voltage to reach apredetermined percentage of the “initial” terminal voltage, determine anovervoltage. In this embodiment, the control circuitry may anticipate,assume and/or estimate a form, shape and/or rate of change of theterminal voltage over time (for example, the form, shape and/or rate ofdecay of the terminal voltage being at a rate of the square root oftime). In this way, the charging techniques and/or circuitry of thepresent inventions may determine, measure and/or monitor theoverpotential of the battery/cell more rapidly.

In another embodiment, the adaptive charging techniques and/or circuitryof the present inventions may determine, measure and/or monitor theoverpotential of the battery/cell by measuring, sampling and/ormonitoring the change in terminal voltage of the battery/cell inresponse to a plurality of temporally contiguous or sequential packets.(See, for example, FIGS. 5A and 5B). In this embodiment, the controlcircuitry sums or accumulates the change in terminal voltage of thebattery/cell (as measured by the monitoring circuitry) over a pluralityof temporally contiguous or sequential packets (for example, 100 to10,000 and preferably 100 to 2,000 packets). Based on the sum of thechange in terminal voltage of the battery/cell over a plurality oftemporally contiguous or sequential packets, the control circuitry maydetermine the overpotential of the battery/cell.

Regardless of the measuring, monitoring and/or determining techniques,the adaptive charging techniques and circuitry of the present inventionsmay adapt, adjust and/or control characteristics of the charge orcurrent signals applied to or injected into the battery/cell (forexample, amount of the applied charge or current) based on or using datawhich is representative of the overpotential of the battery/cell. Here,the control circuitry may adjust characteristics of the charge orcurrent signals (for example, the amount of charge or current for agiven temporal period) applied to or injected into the battery/cellduring the charging process (via control of the charging circuitry) tocontrol the overpotential of the battery/cell so that the overpotentialof the battery/cell is below a predetermined value and/or within apredetermined range.

For example, where the charging techniques and/or circuitry apply chargepackets, having one or more charge pulses, to the battery/cell during acharging sequence, cycle or operation, in one embodiment, the chargingtechniques and/or circuitry may adapt, adjust and/or control theamplitude and/or pulse width and/or duty cycle of the charge or currentpulses of one or more packets applied to or injected into thebattery/cell (for example, the immediately subsequent packets) so thatthe overpotential of the battery/cell in response to such subsequentcharge packet(s) is within a predetermined range. In this embodiment,the charging techniques and/or circuitry may adapt, adjust and/orcontrol one or more characteristics of the charge or current applied toor injected into the battery/cell via adapting, adjusting and/orcontrolling the shape, amplitude and/or width of charge pulse(s) of thesubsequent packet(s).

The predetermined range for the overpotential may be determined based onempirical data, test data, simulation data, theoretical data and/or amathematical relationship. For example, based on empirical data, theadaptive charging techniques and/or circuitry associated with a givenbattery/cell (for example, a certain series, manufacturing lot,chemistry and/or design) may determine, calculate, estimate and/oremploy a predetermined range as well as changes therein. Thepredetermined range for the overpotential may be fixed or may change,for example, based on based on one or more conditions or states of thebattery/cell (for example, SOC and/or SOH and/or temperature).

Thus, in one embodiment, the predetermined range may change based on,for example, a condition or state of the battery/cell. Here, thecircuitry and/or techniques of the present inventions may adjust, changeand/or adapt the predetermined range of the overpotential based on orusing data which is representative of the SOC of the battery/cell and/orthe SOH of the battery/cell.

In one embodiment, based on or using initialization, characterizationand/or calibration data, the adaptive charging techniques and/orcircuitry of the present inventions may calculate, estimate or determinean initial predetermined overpotential range or set of predeterminedovervoltage ranges for the particular battery/cell. For example, in oneembodiment, based on or using (i) initialization, characterizationand/or calibration data and (ii) empirical data, test data, simulationdata, theoretical data and/or a mathematical relationship, the adaptivecharging techniques and/or circuitry of the present inventions maycalculate or determine one or more predetermined ranges for theoverpotential for a particular or associated battery/cell. Indeed, inone embodiment, the adaptive charging techniques and/or circuitry of thepresent inventions, based on or using (i) initialization,characterization and/or calibration data and (ii) empirical data, testdata, simulation data, theoretical data and/or a mathematicalrelationship, may calculate, estimate or determine a pattern orrelationship of the change of the predetermined range of theoverpotential.

Determination or calculation of a predetermined range or set ofpredetermined ranges for the overpotential may also employ data which isrepresentative of a series, manufacturing lot, chemistry and/or designof the battery/cell. In one embodiment, based on empirical data, testdata, simulation data, theoretical data and/or a mathematicalrelationship in conjunction with data which is representative of aseries, manufacturing lot, chemistry and/or design of the battery/cell,one or more predetermined ranges of the overpotential may be determinedor calculate. In addition, one or more changes to such predeterminedoverpotential ranges (which may be based on one or more conditions orstates of the battery/cell and/or responses of the battery/cell to orduring the charging processes) may be determined or calculate,estimated. In yet another embodiment, a predetermined range or set ofpredetermined ranges for the overpotential may be determined orcalculate for a given battery/cell based on or using (i) thebattery/cell response to an initialization, characterization and/orcalibration signals or sequence, and (ii) empirical data, which may, forexample, be developed based on a certain series, manufacturing lot,chemistry and/or design. Notably, data which is representative of apredetermined range or set of predetermined ranges for the overpotentialmay be stored in memory, coupled to the battery/cell, for use by theadaptive charging techniques and/or circuitry of the present inventions.

As indicated above, in one embodiment, an initial predeterminedoverpotential range or set of predetermined overpotential ranges for aparticular battery/cell may be based on or using initialization,characterization or calibration data of the battery/cell. Theinitialization, characterization and/or calibration data may berepresentative of the response of the battery/cell to a characterizationsequence. In one embodiment, the characterization sequence may applycharge signals to the battery/cell. Thereafter, the adaptive chargingtechniques and/or circuitry may evaluate the response to such signals bythe battery/cell. Based thereon, the adaptive charging techniques and/orcircuitry may calculate or determine predetermined overpotential rangesfor the particular battery/cell. Such initialization, characterizationor calibration data may be obtained, acquired and/or determined, forexample, at manufacture, test or calibration which may include thecharacterization sequence to obtain “unique” data regarding a givenbattery/cell.

The initialization, characterization or calibration sequences seek toestablish values for the predetermined limits and ranges discussedearlier. In one embodiment, the initialization, characterization orcalibration sequences measure the overpotential values for newcells/batteries over the full range of SOC. These measurements may befrequent such that 10-50 measurements are made over the full SOC range.In an second embodiment, these values are used to cycle cells/batteries,and correlation data or tables are generated to correlate theseoverpotential values with the capacity fade of the cells/batteries, andconsequently with cycle life. Different values may be used on differentcells to create more complete correlation relationships betweenoverpotential values and capacity fade. Additionally, the overpotentialvalues may be correlated using physical models to the transport oflithium-ions, such as solving Fick's law and current transport lawwithin the cell.

Notably, the predetermined overpotential range or ranges may becalculated or determined by the adaptive circuitry and/or processes ofthe present inventions or by other circuitry and processes (for example,circuitry which is “off-device”, “off-chip” or separate from thecircuitry of the present inventions). The predetermined overpotentialrange or ranges may be stored in memory (for example, in a database orlook-up table) during manufacture, test or calibration, and accessibleto the adaptive circuitry and/or processes of the present inventionsduring operation.

As noted above, the predetermined overpotential ranges may changerelative to initial predetermined ranges in a predetermined manner (forexample, in a fixed relationship over time/use—which may be based on orusing empirical data, test data, simulation data, theoretical dataand/or a mathematical relationship). In addition thereto, or in lieuthereof, such predetermined overpotential ranges may depend onconsiderations such as the state or status of one or more parameters ofthe battery/cell including, for example, the SOC, the SOH and/ortemperature of the battery/cell.

For example, in one embodiment, the predetermined ranges for theoverpotential depend on the SOC of the battery/cell. In this regard, asnoted above, the adaptive charging circuitry and techniques may apply orinject a higher current or charge into the battery/cell when the SOC ofthe battery/cell is low and a lower current or charge when the SOC ofthe battery/cell is high. At a low SOC, the diffusion rate of lithiumions into the electrodes may be faster than the diffusion rate at a highSOC. The difference in diffusion rate can vary substantially.Additionally, it may be beneficial to use a higher charging current whenthe impedance (in particular, the real part thereof, which isrepresentative of the resistance that the battery/cell exhibits to anapplied electrical current) is low and a lower charging current when theimpedance is high. Therefore, in one embodiment, the adaptive chargingalgorithm or technique tailors, changes and/or adjusts the chargingcurrent to control, manage and/or reduce the change in voltage inresponse to such charging current.

The predetermined overpotential range or ranges may be stored inpermanent, semi-permanent or temporary memory. In this regard, thememory may store data, equations, relationships, database and/or look-uptable in a permanent, semi-permanent or temporary (for example, untilre-programmed) memory of any kind or type (for example, EEPROM, Flash,DRAM and/or SRAM). Moreover, the memory may be discrete or resident on(i.e., integrated in) other circuitry of the present inventions (forexample, control circuitry). In one embodiment, the memory may beone-time programmable, and/or the data, equations, relationships,database and/or look-up table of the predetermined overpotentialrange(s) may be stored in a one-time programmable memory (for example,programmed during test or at manufacture). In another embodiment, thememory is more than one-time programmable and, as such, thepredetermined overpotential range(s) may be updated, written, re-writtenand/or modified after initial storage (for example, after test and/ormanufacture) via external or internal circuitry.

As mentioned above, in certain embodiments, two considerations inconnection with implementing the adaptive charging circuitry andtechniques of the present inventions are to:

-   -   i. Minimize and/or reduce total charging time: For practical        reasons, the battery/cell is charged within a given period of        time (for example, a maximum allowed period of time). Typically,        a specification value is defined or chosen depending on the        application. For example, it is approximately 2 to 4 hours for        batteries employed in consumer applications, and for batteries        employed in transportation applications, it may be up to 8        hours. This results in a specification for a net effective        charging current; and    -   ii. Maximize and/or increase cycle life: To maximize and/or        increase cycle life of the battery/cell, it may be desirable to        charge the battery/cell (i) at a low current and/or (ii) provide        rest periods between or in periods of charging (for example,        between charging signals or packets) wherein no charge is        applied to or injected into the battery/cell.        Thus, in certain aspects, the charging circuitry of the present        inventions implement adaptive techniques which seek to (i)        minimize and/or reduce total charging time of the battery/cell        and (ii) maximize and/or increase the cycle life of the        battery/cell (by, for example, minimizing and/or reducing        degradation mechanisms of the charging operation).

With reference to FIGS. 1A-1C and, in one exemplary embodiment, chargingcircuitry 12 may apply one or more charging signals (which provide a netinput of charge or current into the battery/cell) and one or moredischarging signals (which provide a net removal of charge or currentfrom the battery/cell). (See, for example, FIGS. 2C and 2D). As notedabove, the adaptive charging circuitry and techniques of the presentinventions may employ any charging circuitry 12, whether describedherein, now known or later developed, to charge the battery/cell; allsuch charging circuitry 12 are intended to fall within the scope of thepresent inventions. For example, charging circuitry 12 of the presentinventions may generate charging and discharging signals, packets andpulses (as described herein). Notably, charging circuitry 12 isgenerally responsive to control signals from control circuitry 16.

With continued reference to FIG. 1A, monitoring circuitry 14 monitors,senses, detects and/or samples, on an intermittent, continuous and/orperiodic basis, condition or characteristics of the battery/cellincluding, for example, the terminal voltage, open circuit voltage (OCV)and/or temperature of the battery/cell. As noted above, the adaptivecharging circuitry and techniques of the present inventions may employany monitoring circuitry 14 and/or monitoring techniques, whetherdescribed herein, now known or later developed, to acquire such data;all such monitoring circuitry 14 and monitoring techniques are intendedto fall within the scope of the present inventions. The monitoringcircuitry 14 provides data which is representative of the condition orcharacteristics of the battery/cell to control circuitry 16.

The control circuitry 16, using data from monitoring circuitry 14,calculates, estimates, determines and/or assesses the state or conditionof the battery/cell in connection with the charging or rechargingprocess. For example, control circuitry 16 calculates, determines and/orestimates an overpotential of the battery/cell in response to charge orcurrent applied to or injected into the battery/cell. Based thereon,control circuitry 16 adapts, adjusts and/or controls one or morecharacteristics of the charge or current applied to or injected into thebattery/cell (via controlling the operation of charging circuitry 12) sothat the overpotential of the battery/cell (in response to charge orcurrent applied to or injected into the battery/cell during a chargingor recharging sequence/operation) is below a predetermined value and/orwithin a predetermined range.

As discussed above, in one embodiment, where charging circuitry 12applies charge packets (having one or more charge pulses) to thebattery/cell, control circuitry 16 (implementing, for example, one ormore of the inventive adaptive charging techniques described herein)adapts, adjusts and/or controls the characteristics of the chargepackets applied to or injected into the battery/cell (via controllingcharging circuitry 12) so that the overpotential of the battery/cellduring charging (via charge packets) is within a predetermined range.For example, control circuitry 16 may instruct charging circuitry 12 tochange the amount of charge or current applied to or injected into thebattery/cell via controlling the shape, amplitude and/or width of chargepulse(s). In this way, control circuitry 16 may, in one embodiment,adapt, adjust and/or control the charge or current applied to orinjected into the battery/cell (via controlling charging circuitry 12)so that the overpotential of the battery/cell in response to the chargeor current is below a predetermined value and/or within a predeterminedrange.

In another embodiment, charging circuitry 12 applies charge packets,having one or more charge pulses and one or more discharge pulses, tothe battery/cell during a charging or recharging sequence, operation orcycle. In this embodiment, control circuitry 16 may adapt, adjust and/orcontrol (i) the characteristics of charge pulses applied and/or (ii) thecharacteristics of the discharge pulse so that the overpotential of thebattery/cell is below a predetermined value and/or within apredetermined range. Here again, control circuitry 16 (via control ofcharging circuitry 14) may adapt, adjust and/or control the amount ofcurrent applied or injected into the battery/cell via adapting,adjusting and/or controlling the shape, amplitude and/or width of chargepulse(s) and the shape, amplitude and/or width of discharge pulse(s)(via control of charging circuitry 14) in a manner so that overpotentialof the battery/cell due to the charging is below a predetermined valueand/or within a predetermined range. Thus, in these embodiments, controlcircuitry 16 (implementing, for example, one or more of the inventiveadaptive charging techniques described herein) adapts, adjusts and/orcontrols one or more characteristics of the charge and/or dischargepulses so that overpotential of the battery/cell due to the charging isbelow a predetermined value and/or within a predetermined range.

In operation, charging circuitry 12 applies a charge or current to thebattery/cell. (See, for example, the exemplary charge waveforms of FIGS.2A-2D). In one embodiment, monitoring circuitry 14 measures or detectsvoltages at the terminals of the battery/cell. Once the battery/cellreaches full equilibrium (which may be characterized as when theterminal voltage of the battery/cell is relatively constant orunchanging under no charging current), monitoring circuitry 14 measures,samples and/or monitors the terminal voltage of the battery/cell. Thecontrol circuitry 16 may determine or measure the overpotential of thebattery/cell as the difference between these two terminal voltages.

In addition thereto or in lieu thereof, monitoring circuitry 12 andcontrol circuitry 16 may determine, measure and/or monitor theoverpotential of the battery/cell by measuring, sampling and/ormonitoring the terminal voltage of the battery/cell after termination ofa charging signal and, based on or using the characteristics of thedecay of the terminal voltage after terminating the charging signal,control circuitry 16 may derive, calculate, estimate, and/or determinethe overpotential. For example, control circuitry 16 may determine theoverpotential by extrapolating from the terminal voltage of thebattery/cell after termination of a charging signal and thecharacteristics of the decay of the terminal voltage. In one embodiment,monitoring circuitry 12 may measure, sample and/or monitor an “initial”terminal voltage of the battery/cell after terminating the chargingsignal (for example, immediately or substantially immediately afterterminating the charge signal) and, based on the amount of time requiredfor the terminal voltage to reach a predetermined percentage of the“initial” terminal voltage, determine an overvoltage. In thisembodiment, control circuitry 16 may anticipate, assume and/or estimatea form, shape and/or rate of change of the terminal voltage over time(for example, the form, shape and/or rate of decay of the terminalvoltage being at a rate of the square root of time).

In another embodiment, monitoring circuitry 12 and control circuitry 16may determine, measure and/or monitor the overpotential of thebattery/cell by measuring, sampling and/or monitoring the change interminal voltage of the battery/cell in response to a plurality oftemporally contiguous or sequential packets. In this embodiment, controlcircuitry 16 sums or accumulates the change in terminal voltage of thebattery/cell (as measured by monitoring circuitry 12) over a pluralityof temporally contiguous or sequential packets (for example, 100 to50,000 and preferably 1,000 to 20,000 packets). Based on the sum of thechange in terminal voltage of the battery/cell over a plurality oftemporally contiguous or sequential packets, control circuitry 16 maydetermine the overpotential of the battery/cell. In this embodiment, theoverpotential (OP) may be characterized as:

OP∝Σ_(i=1) ^(n)DeltaVi;

-   -   where DeltaV_(i) is the change in terminal voltage, in response        to a charge and/or discharge packet, of the battery/cell. (See,        e.g., Delta V_(i)=V₃−V₁ in FIG. 5A and V_(i)=V₅−V₁ in FIG. 5B).

Regardless of the measuring, monitoring and/or determining techniques,the adaptive charging techniques and circuitry of the present inventionsmay adapt, adjust and/or control characteristics of the charge orcurrent signals applied to or injected into the battery/cell (forexample, amount of the applied charge or current) based on or using datawhich is representative of the overpotential of the battery/cell. Here,control circuitry 16 may adjust the amount of charge or current appliedto or injected into the battery/cell during the charging process (viacontrol of charging circuitry 12) to control the overpotential of thebattery/cell so that the overpotential of the battery/cell is below apredetermined value and/or within a predetermined range.

With reference to FIG. 16, where the change in terminal voltage is belowa predetermined value and/or within a predetermined range, controlcircuitry 16, in one embodiment, instructs charging circuitry 14 toapply the same or similar charge to the battery/cell during subsequentcharging (subject to other considerations including SOC, SOH, partialrelaxation time, change in terminal voltage in response to a packet).Where, however, the change in terminal voltage is greater than thepredetermined value and/or outside the predetermined range (i.e., isless than or is greater than the predetermined range), control circuitry16 adapts, adjusts and/or controls one or more characteristics of thecharge or current applied to or injected into the battery/cell (viacharging circuitry 14) so that a change in voltage at the terminals ofthe battery/cell in response to subsequent charging (for example, theimmediately subsequent charge packet) is below a predetermined valueand/or within a predetermined range. Here, control circuitry 16calculate or determines a change to one or more characteristics of thecharging (for example, the amount of current injected or applied to thebattery/cell) so that charge or current applied to or injected into thebattery/cell via subsequent charging is within a predetermined range.Notably, the predetermined range may indeed change, for example,according to a predetermined rate or pattern, and/or according to themeasured, determined and/or estimated SOC and/or SOH of thebattery/cell.

In particular, with reference to FIGS. 1A-1C and 15B, in one embodiment,monitoring circuitry 14 measures, samples and/or determines the terminalvoltage response to the charge pulse and provides data which isrepresentative of a first voltage (V₁), which correlates to a terminalvoltage of the battery/cell at the end/termination of the charge signal,and a second voltage (V₂), which correlates to a voltage which is apredetermined percentage of the first voltage. The monitoring circuitryand/or the control circuitry may also determine the amount of timebetween these two voltages (T₂−T₁). Based on or using such data, controlcircuitry 16 calculates, determines and/or estimates the overpotentialby extrapolating from the terminal voltage of the battery/cell aftertermination of a charging signal and the characteristics of the decay ofthe terminal voltage. In this embodiment, control circuitry 16 mayanticipate, assume and/or estimate a form, shape and/or rate of changeof the terminal voltage over time (for example, the form, shape and/orrate of decay of the terminal voltage being at a rate of the square rootof time) to determine an overpotential of the battery/cell.

Similarly with reference to FIGS. 1A-1C and 15C, in another embodiment,monitoring circuitry 14 measures, samples and/or determines the terminalvoltage response to the charge pulse and provides data which isrepresentative of a first voltage (V₁), which correlates to a terminalvoltage of the battery/cell at the beginning/initiation of the chargesignal, and a second voltage (V₂), which correlates to a voltage whichis a predetermined percentage of the first voltage. The monitoringcircuitry and/or the control circuitry may also determine the amount oftime between these two voltages (T₂−T₁). As noted above, based on orusing such data, control circuitry 16 calculates, determines and/orestimates the overpotential by extrapolating from the terminal voltageof the battery/cell after termination of a charging signal and thecharacteristics of the decay of the terminal voltage. The controlcircuitry 16 may again anticipate, assume and/or estimate a form, shapeand/or rate of change of the terminal voltage over time (for example,the form, shape and/or rate of decay of the terminal voltage being at arate of the square root of time) to determine an overpotential of thebattery/cell.

Where control circuitry 16 calculates, determines and/or estimates theoverpotential to be below a predetermined value and/or within apredetermined range, control circuitry 16 may not change thecharacteristics of subsequent charge packets due thereto (althoughcontrol circuitry 16 may indeed change such characteristics as a resultof other considerations, such as, for example, considerationsmeasurements of—change in terminal voltage due to charge packets,relaxation time to partial equilibrium, the SOC and/or SOH). Where,however, control circuitry 16 determines the change in terminal voltageis outside the predetermined range, control circuitry 16 may change oneor more characteristics of the charge packet including the shape,amplitude and/or width of charge pulse(s) in order to adapt, adjustand/or control the amount of charge or current applied to or injectedinto the battery/cell (via charging circuitry 14) so that theoverpotential of the battery/cell in response to a subsequent charge orcurrent is within below a predetermined value and/or within apredetermined range. For example, where the change in terminal voltagein response to one or more charge packets is less than a predeterminedrange, control circuitry 16 may increase the amplitude and/or width ofthe charge pulse(s) to thereby inject more current or charge into thebattery/cell in a subsequent packet (for example, the immediatelysubsequent packet). Alternatively, control circuitry 16 may increase theamplitude and decrease the width of the charge pulse(s) to therebyinject the same amount of current or charge into the battery/cell in asubsequent packet (for example, the immediately subsequent packet) butat a higher amplitude relative to the previous packet/pulse.

Where, the change in terminal voltage in response to one or more chargepackets is greater than the predetermined value and/or predeterminedrange, control circuitry 16 may decrease the amplitude and/or width ofthe charge pulse(s) to thereby inject less current or charge into thebattery/cell in the subsequent packet (for example, the immediatelysubsequent packet). Alternatively, control circuitry 16 may decrease theamplitude and increase the width of the charge pulse(s) to therebyinject the same amount of current or charge into the battery/cell in asubsequent packet (for example, the immediately subsequent packet) butat a lower amplitude relative to the previous pulse. (See, for example,FIG. 6A).

Notably, with reference to FIGS. 6A and 6B, in one embodiment, controlcircuitry 16 may adapt, adjust and/or control the amplitude and/orduration of the charge pulse as well as the duration of the rest period(T_(rest)). For example, in one embodiment, control circuitry 16, viacharging circuitry 12, adjusts the amplitude and duration of the chargepulse and the duration of the rest period (T_(rest)) to maintain aconstant period of the charge packet (T_(packet)). Alternatively,control circuitry 16 may adapt, adjust and/or control the duration ofthe rest period (T_(rest)) to accommodate other considerations andparameters in relation to the response of the battery/cell to charging,for example, change in terminal voltage in response to one or morecharge and/or discharge packets and/or relaxation time topartial-equilibrium of the battery/cell.

Thus, control circuitry 16 may adapt, adjust and/or control shape,amplitude and/or width of charge pulse(s) and the shape, amplitudeand/or width of discharge pulse(s) (via controlling charging circuitry14) in a manner so that the overpotential of the battery/cell is below apredetermined value and/or within a predetermined range duringsubsequent charging.

With continued reference to FIG. 5B, control circuitry 16 may, inaddition to controlling the amplitude and width of the charge and/ordischarge pulses, may control the duration of one or both of the restperiods (T_(inter) and T_(rest)). In one embodiment, control circuitry16, via charging circuitry 12, adjusts the amplitude and width of thecharge and/or discharge pulses and duration of one or both of the restperiods (T_(inter) and T_(rest)) to maintain a constant period of thecharge packet (T_(packet)). Alternatively, control circuitry 16 mayadapt, adjust and/or control the amplitude and/or duration of the chargeand/or discharge pulses in relation to the change in terminal voltage ofthe battery/cell as well as adapt, adjust and/or control the duration ofone or both of the rest periods (T_(inter) and T_(rest)) to, forexample, accommodate other considerations and parameters in relation tothe response of the battery/cell to charging (for example, relaxationtime to partial-equilibrium of the battery/cell).

In connection with overpotential, the predetermined limit and/orpredetermined range may be fixed or may change or be adjusted, forexample, over time or use and/or based on one or more conditions orstates of the battery/cell and/or responses of the battery/cell to orduring charging. In one embodiment, the predetermined limit and/orpredetermined range is based on empirical data, test data, simulationdata, theoretical data and/or a mathematical relationship. For example,based on empirical data, control circuitry 16 associated with thebattery/cell may determine, calculate, estimate and/or employpredetermined ranges based on one or more conditions or states of thebattery/cell (for example, the SOC and/or SOH of the battery/cell)and/or responses of the battery/cell to or during charging. Suchpredetermined ranges fixed (for example, conform to a fixed orpredetermined pattern) or may be variable.

In one embodiment, the changes in the predetermined limit and/orpredetermined range may be based on one or more conditions or states ofthe battery/cell and/or responses of the battery/cell to or during thecharging process. For example, the predetermined range may change and/oradapt based on or according to one or more parameters of thebattery/cell including, for example, the SOC, the SOH, change interminal voltage in response to a packet and/or relaxation time (topartial-equilibrium of the battery/cell). In one embodiment, where thebattery/cell is a typical rechargeable lithium-ion (Li+) battery/cellemploying a conventional chemistry, design and materials, apredetermined range may be dependent on the SOC of the battery/cell andmay range between 10 mv and 125 mv depending on the particularchemistry, design and materials of the battery and the SOC of thebattery. For example, in one embodiment, the predetermined range may be(i) 100 mV±5% when the battery SOC is 0-5%, (ii) 60 mV±5% when thebattery/cell includes a SOC of between 5-20%, (iii) 50 mV±5% when thebattery/cell includes a SOC of between 20-40%, (iv) 40 mV±5% when thebattery/cell includes a SOC of between 40-60%, (v) 30 mV±5% when thebattery/cell includes a SOC of between 60-80%, (vi) 25 mV±5% when thebattery/cell includes a SOC of between 80-100%. These values maycollectively be modified and/or reduced as a function of SOH.

Indeed, as mentioned above, in one exemplary embodiment, the neteffective charging current at 0-20% SOC may be 1-1.5 C, and at 80-100%SOC, it may be reduced to 0.1-0.4 C. Notably, the taper of the change innet effective charging current over time may be linear or non-linear(for example, square root of time which is typical of diffusion-limitedtransport dynamics). (See, for example, FIG. 7). It is also possible tomake the net effective charging current initially low for an SOC lessthan 10%, then make it reach a maximum around 5-20% SOC, then graduallymake it decline to a lower value near 90-100% SOC. All of these arevarious embodiments of the taper function of the net effective chargingcurrent with the purpose of optimizing the charging current and chargingtime while taking into account the underlying physical mechanisms in thebattery, for example, mass transport of lithium ions, reaction kineticsand/or their associated time constants, and/or the strains in the anodeduring the intercalation of the lithium ions.

Thus, in one embodiment, control circuitry 16 may calculate, determineand/or employ one or more predetermined ranges based on the status orstate of the battery/cell (for example, based on or using data which isrepresentative of the SOC of the battery/cell, the SOH of thebattery/cell and/or partial relaxation time). That is, the predeterminedrange employed by control circuitry 16 and upon which the change interminal voltage is evaluated, may be dependent on status or state ofthe battery/cell, for example, the SOC of the battery/cell and the SOHof the battery/cell.

In one embodiment, based on or using initialization, characterizationand/or calibration data, control circuitry 16 or external circuitry maycalculate or determine an initial set predetermined limits and/orpredetermined ranges of the overpotential for the particularbattery/cell. For example, in one embodiment, based on or using (i)initialization, characterization and/or calibration data and (ii)empirical data, test data, simulation data, theoretical data and/or amathematical relationship, control circuitry 16 or external circuitrymay calculate, estimate or determine a set of predetermined limitsand/or predetermined ranges for a particular or associated battery/cell.Such predetermined limits and/or ranges of the overpotential may bebased on one or more states of the battery/cell (for example, SOC of thebattery). Indeed, control circuitry 16 may adaptively adjust thepredetermined ranges over the life or use of the battery/cell—forexample, based on the changing conditions of the battery/cell (forexample, a measured SOH of the battery/cell).

Notably, a set of predetermined limits and/or predetermined ranges ofthe overpotential may be calculated or determined by control circuitry16 or by circuitry other than control circuitry 16 (for example,circuitry which is “off-device” or “off-chip” relative to controlcircuitry 16). The predetermined limits or ranges may be stored inmemory (for example, in a database or look-up table) during manufacture,test or calibration, and accessible to the adaptive circuitry and/orprocesses of the present inventions during operation.

In one embodiment, a set of predetermined limits and/or predeterminedranges of the overpotential (based on, for example, SOC and/or SOH ofthe battery/cell) may be calculated or determined and stored in memory(for example, during manufacture, test or calibration). Thereafter,control circuitry 16 may adjust or adapt the set of predetermined limitsand/or predetermined ranges of the overpotential based on the conditionof the battery/cell—for example, the SOC or SOH of the battery/cell.Alternatively, the memory may store multiple sets of predeterminedlimits and/or predetermined ranges (for example, in a look-up table ormatrix) and control circuitry 16 employs a given predetermined rangebased on one or more conditions of the battery/cell—including SOC andSOH of the battery/cell. Thus, in this embodiment, the predeterminedranges employed by control circuitry 16 depends on the SOH of thebattery/cell, which designates or “identifies” a set of predeterminedlimits and/or predetermined ranges, and the SOC of the battery/cellwhich designates or “identifies” the particular predetermined limitsand/or predetermined range within the set of predetermined ranges. Inthese embodiments, control circuitry 16 adapts the control of thecharging process based on or in response to a degrading SOC and SOH ofthe battery/cell. The set of predetermined limits and/or predeterminedranges may also be depend on other considerations such as the state orstatus of other parameters of the battery/cell including, for example,the change in voltage of the battery/cell in response to each packet,relaxation time and/or temperature of the battery/cell (for example, inone embodiment, the predetermined limits or ranges of the overpotentialmay increase with an increase in temperature of the battery/cell).

The predetermined limits or predetermined ranges of the overpotentialmay be stored in any memory now known or later developed; all of whichare intended to fall within the scope of the present inventions. Forexample, the memory may be a permanent, semi-permanent or temporarymemory (for example, until re-programmed). In one embodiment, the memorymay be one-time programmable, and/or the data, equations, relationships,database and/or look-up table of the predetermined range(s) may bestored in a one-time programmable memory (for example, programmed duringtest or at manufacture). In another embodiment, the memory is more thanone-time programmable and, as such, the predetermined range(s) may beupdated, written, re-written and/or modified after initial storage (forexample, after test and/or manufacture) via external or internalcircuitry.

With reference to FIGS. 1A-1C, memory 18 may be integrated or embeddedin other circuitry (for example, control circuitry 16) and/or discrete.The memory 18 may be of any kind or type (for example, EEPROM, Flash,DRAM and/or SRAM). The memory 18 may store data which is representativeof the predetermined ranges, equations, and relationships. Such data maybe contained in a database and/or look-up table.

As noted above, in certain embodiments, two considerations in connectionwith implementing the adaptive charging circuitry and techniques of thepresent inventions include (i) minimizing and/or reducing total chargingtime and (ii) maximizing and/or increasing cycle life. This results in aspecification for a net effective charging current. Moreover, tomaximize and/or increase cycle life of the battery/cell, it may bedesirable to charge the battery/cell (i) at a low current and/or (ii)provide relaxation or rest periods between charging periods. Thus, incertain aspects, the charging circuitry of the present inventionsimplement adaptive techniques which seek to (i) minimize and/or reducetotal charging time of the battery/cell and (ii) maximize and/orincrease the cycle life of the battery/cell (by, for example, minimizingand/or reducing degradation mechanisms of the charging operation).

In one embodiment, control circuitry 16 may evaluate the overpotentialof the battery/cell less than ten times per charge cycle. In a preferredembodiment, control circuitry 16 evaluates the overpotential of thebattery/cell between four and eight times per charge cycle. Moreover, inone embodiment, when the SOC of the battery/cell is greater than apredetermined value (for example, in one embodiment, greater than 80%,and in a preferred embodiment, greater than 90%), control circuitry 16terminates (i) determining, measuring and/or monitoring theoverpotential (via measuring or monitoring the terminal voltage) of thebattery/cell, and/or (ii) determining whether the overpotential is belowa predetermined value and/or within a predetermined range, and/or (iii)adapting, adjusting and/or controlling characteristics of the charge orcurrent signals applied to or injected into the battery/cell (forexample, amount of the applied charge or current) so that theoverpotential of the battery/cell to such charging is below apredetermined value and/or within a predetermined range. In thisembodiment, while control circuitry 16 determines, measures and/ormonitors the overpotential when the SOC of the battery/cell is less thana predetermined value (for example, using any of the techniquesdescribed herein), control circuitry 16 may cease (i) determining,measuring and/or monitoring the overpotential (via measuring ormonitoring the terminal voltage) of the battery/cell, and/or (ii)determining whether the overpotential is below a predetermined valueand/or within a predetermined range, and/or (iii) adapting, adjustingand/or controlling characteristics of the charge or current signalsapplied to or injected into the battery/cell (for example, amount of theapplied charge or current) when the SOC of the battery/cell is greaterthan the predetermined value (for example, in 80% of SOC or 90% of SOC).

As noted above, although the aforementioned discussion refers tooverpotential, that discussion is applicable to full relaxation time ofthe battery/cell in addition to overpotential. As such, the adaptivecharging techniques and/or circuitry of the present inventions may (i)determine, measure and/or monitor the full relaxation time (viameasuring or monitoring the terminal voltage) of the battery/cell on anintermittent, continuous and/or periodic basis, (ii) determine whetherthe full relaxation time is below a predetermined value and/or within apredetermined range on an intermittent, continuous and/or periodicbasis, and/or (iii) adapt, adjust and/or control characteristics of thecharge or current signals applied to or injected into the battery/cell(for example, amount of the applied charge or current) so that the fullrelaxation time of the battery/cell to such charging is below apredetermined value and/or within a predetermined range on anintermittent, continuous and/or periodic basis. For the sake of brevity,that discussion will not be repeated in connection with full relaxationtime.

There are many inventions described and illustrated herein. Whilecertain embodiments, features, attributes and advantages of theinventions have been described and illustrated, it should be understoodthat many others, as well as different and/or similar embodiments,features, attributes and advantages of the present inventions, areapparent from the description and illustrations. As such, theembodiments, features, attributes and advantages of the inventionsdescribed and illustrated herein are not exhaustive and it should beunderstood that such other, similar, as well as different, embodiments,features, attributes and advantages of the present inventions are withinthe scope of the present inventions. Indeed, the present inventions areneither limited to any single aspect nor embodiment thereof, nor to anycombinations and/or permutations of such aspects and/or embodiments.Moreover, each of the aspects of the present inventions, and/orembodiments thereof, may be employed alone or in combination with one ormore of the other aspects of the present inventions and/or embodimentsthereof.

For example, the adaptive charging techniques and circuitry of thepresent inventions may monitor and/or determine one or more (or all) ofthe parameters discussed herein (including, for example, (i) change interminal voltage in response to one or more charge/discharge pulses,(ii) partial relaxation time, (iii) SOC of the battery/cell, (iv) fullrelaxation time or overpotential and/or (v) SOH (or changes therein) ofthe battery/cell) and responsively adapt the characteristics of thecharging sequence (for example, the amount of charge, length andrelative location of rest periods, the amplitude of the chargingsignals, the duration or width of the charge or charging signals and/orshape of the charging signals) to control one or more (or all) of suchparameters. The present inventions are neither limited to anycombination and/or permutation of such monitoring and/or adaptation.Indeed, the control circuitry may employ such techniques and/or controlsuch parameters in any combination; all combination or permutationsthereof are intended to fall within the scope of the present inventions.

For example, in one embodiment, the control circuitry, using the stateor status of one or more (or all) of the aforementioned parameters whichare determined at differing rates, adapts, adjusts and/or controls thecharacteristics of the charge injected into the battery/cell (viacontrolling, for example, the shape, amplitude and/or duration of thecurrent signal output by the charging circuitry). With reference to FIG.17A-17E, the control circuitry may implement one or more adaptationloops to determine whether to adapt, adjust and/or control thecharacteristics of the charge injected into the battery/cell (viacontrol of the charging circuitry). For example, the control circuitrymay employ a first adaption loop which monitors and/or determines achange in terminal voltage in response to one or more charge/dischargepulses (of, for example, one or more packets) and/or the partialrelaxation time to responsively adapt the characteristics of thecharging sequence. (See, for example, FIG. 18A). Here, the controlcircuitry may monitor and/or determine the parameters of the first loopand/or responsively adapt the characteristics of the charging sequencebased on or using the parameters of the first loop at a first rate (forexample, 1 to 100 ms).

In addition thereto, or in lieu thereof, the control circuitry mayemploy a second adaption loop which determines or estimates the SOC ofthe battery/cell and/or the full relaxation time or overpotential toresponsively adapt the characteristics of the charging sequence. (See,for example, FIG. 18B). Here, the control circuitry may monitor and/ordetermine or estimates the parameters of the second loop and/orresponsively adapt the characteristics of the charging sequence based onor using the parameters of the second loop at a second rate (which isless than the first rate—for example, 1 to 1000 seconds).

The control circuitry may, in addition thereto or in lieu thereof,employ a third adaption loop which determines or estimates the SOH (orchanges therein) of the battery/cell to responsively adapt thecharacteristics of the charging sequence. (See, for example, FIG. 18C).Here, the control circuitry may monitor and/or determine or estimate theparameter of the third loop and/or responsively adapt thecharacteristics of the charging sequence based on or using the parameterof the third loop at a third rate (which is less than the first andsecond rates—for example, after a predetermined number of charge and/ordischarge cycles (for example, 1-10 charge and/or discharge cycles)).

Notably, the control circuitry may, in addition thereto or in lieuthereof, employ a fourth adaption loop which determines or estimates thetemperature (or changes therein) of the battery/cell during charging toresponsively adapt the characteristics of the charging sequence. (See,for example, FIG. 18D). Here, the control circuitry may monitor and/ordetermine or estimate the temperature of the battery/cell and/orresponsively adapt the characteristics of the charging sequence based onor using the temperature of the battery/cell at a fourth rate (which isdifferent from the first, second and/or third rates—for example, every 5minutes and/or during a SOC determination or estimation).

With reference to FIG. 17E, the control circuitry may implement atechnique that includes N adaption loops (where N is a naturalnumber—i.e., 1, 2, . . . ) wherein the control circuitry determines orestimates the parameters associated with each loop and/or responsivelyadapt the characteristics of the charging sequence based on or using theassociated parameter of each loop at a corresponding rate. Notably, ineach of the above embodiments, the monitoring circuitry may monitor thestate, parameters and/or characteristics of the battery/cell (forexample, terminal voltage) in accordance with the aforementioned ratesand/or continuously, intermittently and/or periodically.

Thus, the adaptive charging techniques and circuitry of the presentinventions may implement one or more adaption loops each based on one ormore different parameter. The present inventions are neither limited toany combination and/or permutation of such adaptation loops. Indeed, thecontrol circuitry may employ such adaption loops alone/separately or inany combination; all combination or permutations thereof are intended tofall within the scope of the present inventions.

The rate at which the control circuitry implements an adaption loop maybe temporally based and/or event based. For example, the controlcircuitry may estimate, calculate, measure and/or determine the SOC orSOH (and/or changes therein) based on one or more events and/or chargingresponse characteristics (for example, the charge retained and/orprovided battery/cell is “inconsistent” with the SOC or SOH data and/orthere is an “inconsistency” between the SOC, SOH, relaxation time and/orthe voltage at the terminals of the battery/cell during charging). Thatis, in one embodiment, in response to detecting one or more events (forexample, a beginning or initiation of a charging sequence/cycle) and/or“triggerable” charging response characteristics (due to, for example, an“inconsistency” between the battery charge response characteristics orparameters which suggests, for example, the SOH (which may be stored inmemory) may not be as estimated or determined), the control circuitryestimates, calculates, measures and/or determines the SOH (and/orchanges therein) of a battery/cell and adapts, adjusts and/or controlsthe amount of charge injected into the battery/cell based on or usingSOH (and/or changes therein) of the battery/cell.

Further, although several of the exemplary embodiments are describedand/or illustrated in the context of circuitry and/or techniques for alithium ion technology/chemistry based battery/cell (for example,lithium-cobalt dioxide, lithium—manganese dioxide, lithium-ironphosphate, and lithium—iron disulfide), the inventions described and/orillustrated herein may also be implemented in conjunction with otherelectrolyte battery chemistries/technologies including, for example,nickel-cadmium and other nickel metal hydride chemistries/technologies.As such, the embodiments set forth in the context of lithium ion basedbatteries/cells are merely exemplary; and other electrolyte batterychemistries/technologies, implementing one or more of the features ofthe present inventions as described herein, are intended to fall withinthe scope of the present inventions. It is to be understood that otherembodiments may be utilized and operational changes may be made withoutdeparting from the scope of the present inventions. Indeed, theforegoing description of the exemplary embodiments of the inventions hasbeen presented for the purposes of illustration and description. It isintended that the scope of the inventions not be limited solely to thedescription above.

Further, as discussed above, the control circuitry may intermittently,continuously and/or periodically estimate, calculate, measure and/ordetermine a change in terminal voltage of the battery/cell in responseto a charge or discharge signal, packet and/or pulse. In additionthereto, the control circuitry may intermittently, continuously and/orperiodically adapt, adjust and/or control the characteristics of thecharge or discharge signal, packet and/or pulse (via controlling, forexample, the shape, amplitude and/or duration of the signal output ofthe charging circuitry) based on whether the change in terminal voltageis within a predetermined range. Thus, in one embodiment, the adaptivecharging techniques and/or circuitry intermittently, continuously and/orperiodically measure or monitor the terminal voltage of thebattery/cell. Based thereon or using such data, the adaptive chargingtechniques and/or circuitry may intermittently, continuously and/orperiodically determine and/or adapt the subsequent charging anddischarging of the battery/cell so that the change in terminal voltageis within a predetermined range. Accordingly, adaptive chargingtechniques and/or circuitry of the present inventions may (i) measure ormonitor the terminal voltage of the battery/cell on an intermittent,continuous and/or periodic basis, (ii) determine whether a change interminal voltage (which is response to charge and discharge pulses) iswithin a predetermined range on an intermittent, continuous and/orperiodic basis, and/or (iii) adapt, adjust and/or controlcharacteristics of the charge or current (for example, amplitude of theapplied charge or current) applied to or injected into the battery/cellso that the change in terminal voltage is within a predetermined rangeon an intermittent, continuous and/or periodic basis. All permutationsand combinations are intended to fall within the scope of the presentinventions. Indeed, such embodiments are applicable to the chargingtechniques and/or circuitry which apply or inject (i) charge packetshaving one or more charge pulses and (ii) charge packets having one ormore charge pulses and one or more discharge pulses.

Moreover, in one embodiment, the exemplary charge and discharge signalsgenerated, output and/or applied by the current charging circuitry tothe battery/cell may be characterized as including a plurality ofpackets (for example, about 1,000 to about 50,000 packets—depending onthe initial SOC and the final SOC), wherein each packet includes aplurality of current pulses (for example, 1 to about 50 pulses in eachpacket). (See, FIGS. 3A-3K and 5A wherein the illustrative exemplarypackets depict various characteristics (for example, a programmablenumber of pulses, pulse shapes, sequence, combination and/or spacing ofcharge and discharge pulses, pulse widths and/or duty cycles)). Thecharge pulses and discharge pulses may be any shape (for example,rectangular, triangle, sinusoidal or square). (See, for example, FIGS.19A-19D and 20A-20D). Moreover, the current or charge pulses may includecharging and discharging pulses (each having fixed, programmable and/orcontrollable shapes, pulse widths and/or duty cycles). (See, forexample, FIGS. 3C-3G and 5B).

In addition, the packets may also include one or more rest periodshaving programmable or controllable durations. That is, each packet mayinclude one or more rest periods wherein each rest period (if more thanone) having a programmable and/or controllable temporal width/duration.(See, for example, FIGS. 5A and 5B).

Notably, in one exemplary embodiment, the charge and/or discharge pulsesof the packet are square shaped including a temporal duration of betweenabout 1 ms and about 100 ms, and preferably less than 30 ms. (See, forexample, FIGS. 5A and 5B). This exemplary packet includes one or twocharge pulses and one discharge pulse (for example, 1:1, 2:1 and/or 3:2charge pulses to discharge pulses) wherein the amplitudes and dutycycles are programmable. (See, for example, FIGS. 5A and 5B). Further,in this exemplary embodiment, each packet includes one rest periodhaving a programmable and/or controllable temporal width/length. In oneexemplary embodiment, the intermediate rest period includes a temporallength or duration of between about 1 ms and about 20 ms. In addition,the rest period, in one exemplary embodiment, includes a temporal lengthor duration of between about 1 ms and about 200 ms. Notably, controlcircuitry 16 adapts the temporal width/length programmable rest periods(for example, the rest period (T_(rest)) in FIGS. 5A and 5B) based on orusing data which is representative of the relaxation time of thebattery/cell.

Indeed, in operation, one, some or all of the characteristics of thecharge pulses and/or discharge pulses are programmable and/orcontrollable via charging circuitry 12 including, for example, theshape, amplitude and/or duration of the pulses. Moreover, the sequenceof the charge and discharge pulses (within a packet) is programmable viacharging circuitry 12. For example, the discharge pulse may precede thecharge pulse and/or the packet may include more charge pulses thandischarge pulses (for example, 2:1 or 3:2 charge pulses to dischargepulses) or more discharge pulses than charge pulses (for example, 2:1 or3:2 charge pulses to discharge pulses).

Moreover, the amplitude of the charge and/or discharge pulses may varywithin the packet (and is/are programmable and/or controllable via thecontrol circuitry), the duration of the charge and/or discharge pulsesmay vary (and is/are programmable and/or controllable via the controlcircuitry), and/or the duration and/or timing of the rest period(s) mayvary within the packet (and is/are programmable and/or controllable viathe control circuitry). Again, the control circuitry may employ suchprogrammable characteristics so that the change in voltage at theterminals of the battery/cell in response to such pulses is within apredetermined range.

As intimated above, the control circuitry may manage, adjust, program,and/or control the amount of charge input into the battery/cell and/orthe amount of charge removed from the battery/cell via the chargingcircuitry. For example, the amount of charge input into the battery/cellmay be controlled via adjusting, controlling and/or modifyingcharacteristics of the charge pulses (for example, pulse amplitude,pulse width/duration and pulse shape). Similarly, the amount of chargeremoved from the battery/cell may be controlled via adjusting,controlling and/or modifying characteristics of the discharge pulses(for example, pulse amplitude, pulse width/duration and pulse shape).

In addition thereto, or in lieu thereof, the control circuitry maymanage, adjust, program, and/or control the ratio of the amount ofcharge input to the battery/cell to the amount of charge removed fromthe battery/cell, over time, via control of the charging circuitry. Inone embodiment, the control circuitry adapts, adjusts and/or controlsthe ratio of charge packets (which input a certain or predeterminedamount of charge into the battery/cell) to discharge packets (whichremove a certain or predetermined amount of charge from thebattery/cell). For example, the control may provide a ratio of betweenfive and ten charge packets to discharge packets, and in a preferredembodiment the ratio is greater than ten.

In addition thereto, or in lieu thereof, in another embodiment, thecontrol circuitry may adjust, program, and/or control the ratio on a perpacket basis (i.e., charge packet and/or discharge packet). In thisregard, the control circuitry adjusts, programs, and/or controls theamount of charge input per packet and the amount of charge removed perpacket to provide, manage, adjust, program, and/or control the ratio ofthe amount of charge input to the battery/cell to the amount of chargeremoved from the battery/cell, over time. Thus, in this exemplaryembodiment, the control circuitry adjust, program, and/or control theratio on a packet-by-packet basis via controlling the chargingcircuitry.

Notably, a smaller ratio of the amount of charge input to the amount ofcharge removed will tend to lengthen the charge time to, for example,less than an optimal value. Under these circumstances, the chargingtechnique is increasing cycle life via increasing charge time. However,as indicated above, in certain aspects, the adaptive charging circuitryand techniques of the present inventions may provide, enhance, control,optimize and/or adjust the charging profile to (i) minimize and/orreduce total charging time and (ii) maximize and/or increase cycle life.As such, in certain embodiments, the adaptive charging circuitry andtechniques of the present inventions may provide, enhance, control,optimize and/or adjust the charging profile to reduce the charging timewithout managing, increasing and/or maximizing the cycle life of thebattery/cell. Similarly, in certain embodiments, the adaptive chargingcircuitry and techniques of the present inventions may provide, enhance,control, optimize and/or adjust the charging profile to increase thecycle life of the battery/cell without managing, reducing and/orminimizing the charging time of the battery/cell.

Thus, the characteristics of the charge pulses and/or discharge pulsesare programmable, controllable and determined by the control circuitrywhen implementing one or more of the adaptive charging techniquesdescribed and/or illustrated herein (charging techniques to adapt,adjust and/or control one or more characteristics of the charge orcurrent applied to or injected into the battery/cell so that the changein voltage at the terminals of the battery/cell is within apredetermined range).

The characteristics of consecutive charge and discharge packets may berepetitive. That is, the combination of charging pulses, dischargingpulses and rest periods may be repetitive, which, in combination form apacket. Such packets of a charge or discharge signal may be repetitive.All combination or permutations of charging pulses and dischargingpulses are intended to fall within the scope of the present inventions.

Notably, such charge signals and discharge signals may be repeated overa charging period. The control circuitry may control, adjust, calculateand/or vary one or more of the parameters or characteristics of thecharging signals and/or discharging signals via controlling one or moreof the constituent packets including the charge pulses, dischargingpulses and rest periods thereof. For example, the parameters orcharacteristics of the charging and/or discharging pulses of one or morepackets of one or more charging and/or discharging signals, namelyshape, durations and/or current amplitudes of the pulses, may beadaptively modified as described herein to implement the adaptivecharging algorithm or techniques described herein. Indeed, in oneembodiment, the duration of the charging signal may be from onemillisecond to several seconds. Moreover, the duration of thedischarging signal (in one embodiment) may be from one millisecond to afew hundreds of milliseconds.

Notably, the adaptive charging technique or algorithm may adaptivelyobtain or provide a predetermined relaxation time or period by adjustingand/or controlling the amount of electrical charge removed during thedischarge period (by, for example, controlling the characteristics ofthe discharge signal(s) and/or period), the amount of electrical chargeadded during the charge period (by, for example, controlling thecharacteristics of the charge signal(s) and/or period), and/or theamount of time of the rest period. All combination or permutationsthereof are intended to fall within the scope of the present inventions.In this regard, each of the charge signals, discharge signals and restperiods may be adapted to control and/or manage the relaxation time ofthe cell of the battery. In addition to adapting the sequence of thecharge signals, discharge signals and rest periods—in relation to eachother—the control circuitry may vary, adjust and/or control one or moreof the variable characteristics of the charge signals, discharge signalsand rest periods. In this way, the control circuitry may obtain orprovide a desired or predetermined relaxation time or period (forexample, a relaxation time that is within prescribed range, by adjustingand/or controlling the amount of electrical charge removed during thedischarge period (by, for example, controlling the characteristics ofthe discharge signal(s) and/or period), the amount of electrical chargeadded during the charge period (by, for example, controlling thecharacteristics of the charge signal(s) and/or period), and/or thecharacteristics of the rest period. In one embodiment, the adaptivecharging technique or algorithm employs a sequence of discharge signalswhere the relaxation time is calculated, determined and/or measuredafter each of the discharge signals. In this way, the control circuitrymay adaptively determine the total amount of electrical charge thatshould be removed (and, in response thereto, control the chargingcircuitry accordingly).

There are numerous permutations involving the amount of electricalcharge added to the battery/cell during the charge or charging signaland the amount of charge removed during the discharging signal. Allpermutations are intended to fall within the scope of the presentinventions. Notably, each permutation may result in a differentrelaxation period. Moreover, within each permutation, there exists alarge number of sub-permutations that i) combine the characteristics ofthe charge or charging signals (for example, the duration, shape and/oramplitude of the charging signal), the product of which determines theamount of electrical charge added to the cell; and ii) combine thecharacteristics of the discharging signal (for example, the duration,shape and/or amplitude of the discharging signal), the product of whichdetermines the amount of electrical charge removed from the cell; andiii) the length of time of the rest period. The characteristics of thecharge or charging signals may differ from the characteristics of thedischarging signals. That is, one or more of the duration, shape and/oramplitude of the charging signal may differ from one or more of theduration, shape and/or amplitude of the discharging signal.

As indicated above, the discharging signal (negative current signal) mayinclude a plurality of discharge pulses and one or more charging pulses.(See, for example, FIGS. 2C, 2D and 3K-3N). The discharge signals removecharge from the battery/cell and may be employed to reduce the timeperiod for the battery/cell terminal voltage to return to equilibrium.In this regard, the discharge period may remove excess charge that hasnot diffused into the anode, and thus may, for example, contribute todegradation mechanisms, examples include the thickening of thesolid-electrolyte interface (SEI) layer or metallic plating of lithium.Clearly, the difference between the electrical charge added to the cellduring the charging signal and the electrical charge removed from thecell during the discharge period determines a net total electricalcharge added to the cell in one period. This net total electrical chargedivided by the period may determine a net effective charging current.All combination or permutations of charging signals and dischargingsignals are intended to fall within the scope of the present inventions.

As stated above, the SOC of a rechargeable battery/cell, for example, alithium-ion battery/cell, is a parameter that is representative ofand/or indicates the level of electrical charge available in thebattery/cell. It may be characterized as a percentage of the nominalfull charge rating of the battery/cell, wherein a 100% SOC indicatesthat a battery/cell is fully charged and a zero reading indicates thatthe battery/cell is fully discharged. (See, for example, (1) “Method andCircuitry to Control Charging of a Rechargeable Battery”, Maluf et al.,U.S. Provisional Patent Application Ser. No. 61/346,953, filed May 21,2010, (2) “Method and Circuitry to Measure the State of Charge andImpedance of a Rechargeable Battery and to Adaptively Control theCharging of Same”, Maluf et al., U.S. Provisional Patent ApplicationSer. No. 61/358,384, filed Jun. 24, 2010, (3) “Method and Circuitry toAdaptively Charge a Rechargeable Battery”, Maluf et al., U.S.Provisional Patent Application Ser. No. 61/368,158, filed Jul. 27, 2010,and (4) “Method and Circuitry to Adaptively Charge a Battery/Cell”,Ghantous et al., U.S. Provisional Application No. 61/439,400, filed Feb.4, 2011).

The present inventions may employ any technique and/or circuitry nowknown or later developed may be employed to estimate, calculate, measureand/or determine parameters of the battery/cell including, for example,the SOC or SOH of a battery/cell. For example, in one embodiment, thepresent inventions employ the techniques and/or circuitry describedand/or illustrated in the U.S. Provisional Patent Applications and, inparticular, the techniques and/or circuitry described and/or illustratedin U.S. Provisional Application Ser. No. 61/358,384 (Inventors: Maluf etal., filed Jun. 24, 2010) to estimate, calculate, measure and/ordetermine the SOC of the battery/cell. In this regard, in oneembodiment, the control circuitry may calculate, measure and/ordetermine the relaxation time (in response to an applied charge, forexample, one or more charge pulses) and thereafter correlate therelaxation time to a SOC of the battery/cell. In addition thereto, or inlieu thereof, the control circuitry may calculate, measure and/ordetermine characteristics of the change in terminal voltage in responseto an applied charge (for example, one or more charge pulses) andthereafter correlate such change in characteristics (for example, thepeak amplitude and/or increase) to a SOC of the battery/cell.

As noted above, in another aspect of the present inventions, thecircuitry and/or techniques measure the SOC of a battery/cell. Here, thecircuitry and/or techniques employ the voltage and current to obtain,measure, monitor, calculate and/or estimate data which arerepresentative of the SOC of the battery/cell. In this regard, thepresent inventions may measure data which is representative of therelaxation time of the battery/cell to one or more charge pulse and,based thereon, determine the SOC of the battery/cell. As mentionedabove, the circuitry and/or techniques may also employ the temperatureof the battery/cell in addition to other parameters. Here, themonitoring circuitry may include one or more temperature sensors (notillustrated) which is/are thermally coupled to the battery/cell togenerate, measure and/or provide data which is representative of thetemperature of the battery/cell.

The data which is representative of the relaxation time may correlate tothe amount of charge added to the battery/cell in response to anapplication of one or more charging pulses, the SOC of the battery/cell,and the temperature of the battery/cell. Using data corresponding to orrepresentative of the relaxation time for a given charge pulse or pulses(and temperature), circuitry and techniques may estimate, derive,determine, calculate, generate and/or obtain the correlation of therelaxation time to the SOC of the battery/cell. In one embodiment, afunctional relationship or look-up table may be determined, estimated,calculated, generated and/or obtained (by circuitry and/or techniquesperformed on-device and/or off-device) which correlates a measuredrelaxation time to the SOC of the battery/cell. The correlation of therelaxation time to the SOC of the battery/cell (for example, theaforementioned relationship or look-up table) may be employed bycircuitry and/or techniques of the present inventions to adapt thecharging profile of the battery/cell based on or using the SOC of thebattery/cell to, for example, alleviate, minimize and/or reduce theadverse impact of the charging operation on the SOH of the battery/celland increase, improve and/or maximize cycle life of the battery/cellthereof.

In addition thereto, or in lieu thereof, the present inventions maymeasure data which is representative of the characteristics (forexample, peak amplitude) of the voltage change (for example, increase)to one or more charge pulse and, based thereon, determine the SOC of thebattery/cell. Using data corresponding to or representative of thecharacteristics (for example, peak amplitude) of the voltage change (forexample, increase) to one or more charge pulse, circuitry and techniquesmay derive, determine, calculate, generate and/or obtain the correlationof a peak amplitude of the voltage change to the SOC of thebattery/cell. In one embodiment, a functional relationship or look-uptable may be determined, calculated, generated and/or obtained whichcorrelates a peak amplitude of the voltage change to the SOC of thebattery/cell. The correlation of the peak amplitude of the voltagechange to the SOC of the battery/cell (for example, the aforementionedrelationship or look-up table may be employed by circuitry and/ortechniques (which may be on-device and/or off-device) to adapt thecharge operation of the battery/cell based on or using the SOC of thebattery/cell. Adaptively controlling the charge profile orcharacteristics may alleviate, minimize and/or reduce the adverse impactof the charging operation on the SOH of the battery/cell and therebyincrease, improve and/or maximize cycle life of the battery/cell.

As intimated above, data which is representative of the SOC of arechargeable battery/cell may be dependent on temperature. With that inmind, the circuitry and techniques for adaptively charging such abattery/cell based on or using the SOC of the battery/cell, may alsoconsider the temperature of the battery/cell in connection with thecharging characteristics of the battery/cell. Thus, while temperaturemay not be necessarily mentioned, such data may be dependent on thetemperature.

Notably, in one embodiment, the relaxation time, measurement of the SOCand/or measurement of overvoltage potential may be implemented viacircuits that apply a short charge pulse or discharge pulse. Suchcircuits may be implemented in the charging circuitry or in measurementcircuitry. For example, in one implementation, a current source is gatedby a switch, and the terminal voltage of the battery/cell is monitored(for example, continuously). In another implementation, circuitry of thecharging circuitry may is employed to generate a short charge ordischarge pulse. For example, a laptop computer or smartphone includesan integrated charging circuit responsible for charging the battery. Thecharging integrated circuit is directly controlled through acommunication bus such as, for example, I2C or SMBus®.

As indicated above, the monitoring circuitry monitors, senses, detectsand/or samples (on an intermittent, continuous and/or periodic basis)characteristics of the battery/cell including, for example, the responseof the battery/cell to one or more charge pulses, the terminal voltagesand the temperature. In one embodiment, the monitoring circuitryincludes a sensor to determine a voltage (for example, a voltmeter)and/or a sensor to determine a current (for example, a current meter).(See, for example, FIG. 1D). The monitoring circuitry and techniques maybe those described herein, now known or later developed, to acquire dataemployed by the control circuitry to adaptive the charging profile ofthe battery; all such monitoring circuitry and techniques are intendedto fall within the scope of the present inventions.

In addition, as mentioned above, the control circuitry acquires the datafrom the monitoring circuitry and, estimates, calculates and/or measuresthe change in voltage in response to the charge/discharge pulses andpackets, relaxation time of the battery/cell to one or more chargepulses, the characteristics (for example, peak amplitude) of the OCV toone or more charge/discharge pulses, and/or the impedance of thebattery/cell and, if appropriate, adapts the charging process bycontrolling the operation of the charging circuitry. The presentinventions may employ any control circuitry and charging circuitrywhether that described herein, now known or later developed, to chargethe battery/cell as well as adapt the charging process.

Further, as noted above, control circuitry may perform or execute one ormore applications, routines, programs and/or data structures thatimplement particular methods, techniques, tasks or operations describedand illustrated herein. The functionality of the applications, routinesor programs may be combined or distributed. In addition, theapplications, routines or programs may be implementing by the controlcircuitry using any programming language whether now known or laterdeveloped, including, for example, assembly, FORTRAN, C, C++, and BASIC,whether compiled or uncompiled code; all of which are intended to fallwithin the scope of the inventions.

Moreover, monitoring circuitry and control circuitry may share circuitrywith each other as well as with other elements. Moreover, such circuitrymay be distributed among a plurality of integrated circuits which mayalso perform one or more other operations, which may be separate anddistinct from that described herein.

As noted above, the charging circuitry responsively applies one or morecurrent or charging signal to the battery/cell to the battery/cell(which may include two terminals). The charging circuitry may also applyone or more charging signals (which provide a net input of charge orcurrent into the battery/cell—for example, one or more charge pulses)and one or more discharging signals (which provide a net removal ofcharge or current from the battery/cell—for example, one or moredischarge pulses which dissipate charge (see, for example, “Recovery ofEnergy from Discharge Pulses”, Berkowitz et al., U.S. ProvisionalApplication Ser. No. 61/360,048, filed Jun. 30, 2011). In oneembodiment, the charging circuitry includes a current source. (See, forexample, FIG. 1D). In addition thereto, or in lieu thereof, the chargingcircuitry may include a voltage source. As discussed herein, thecharging circuitry is responsive to one or more control signals from thecontrol circuitry. (See, for example, FIG. 1D).

Notably, at times, terms battery and cell have been employedinterchangeably to mean an electrical storage device that may beelectrically charged and discharged. Such a device may include a singleelectrical cell, or may include several cells electrically connected inseries and/or parallel to form a battery of larger electrical capacity.It shall be noted that the embodiments for adaptive charging describedabove shall apply to either cells or batteries, as a single unit ormultiple units electrically configured into a larger battery pack.

Notably, a “circuit” means, among other things, a single component (forexample, electrical/electronic) or a multiplicity of components (whetherin integrated circuit form, discrete form or otherwise), which areactive and/or passive, and which are coupled together to provide orperform a desired operation. In addition, “circuitry”, means, amongother things, a circuit (whether integrated or otherwise), a group ofsuch circuits, one or more processors, one or more state machines, oneor more processors implementing software, one or more gate arrays,programmable gate arrays and/or field programmable gate arrays, or acombination of one or more circuits (whether integrated or otherwise),one or more state machines, one or more processors, one or moreprocessors implementing software, one or more gate arrays, programmablegate arrays and/or field programmable gate arrays. The term “data”means, among other things, a current or voltage signal(s) (plural orsingular) whether in an analog or a digital form, which may be a singlebit (or the like) or multiple bits (or the like).

It should be further noted that the various circuits and circuitrydisclosed herein may be described using computer aided design tools andexpressed (or represented), as data and/or instructions embodied invarious computer-readable media, in terms of their behavioral, registertransfer, logic component, transistor, layout geometries, and/or othercharacteristics. Formats of files and other objects in which suchcircuit expressions may be implemented include, but are not limited to,formats supporting behavioral languages such as C, Verilog, and HLDL,formats supporting register level description languages like RTL, andformats supporting geometry description languages such as GDSII, GDSIII,GDSIV, CIF, MEBES and any other suitable formats and languages.Computer-readable media in which such formatted data and/or instructionsmay be embodied include, but are not limited to, non-volatile storagemedia in various forms (e.g., optical, magnetic or semiconductor storagemedia) and carrier waves that may be used to transfer such formatteddata and/or instructions through wireless, optical, or wired signalingmedia or any combination thereof. Examples of transfers of suchformatted data and/or instructions by carrier waves include, but are notlimited to, transfers (uploads, downloads, e-mail, etc.) over theInternet and/or other computer networks via one or more data transferprotocols (e.g., HTTP, FTP, SMTP, etc.).

Indeed, when received within a computer system via one or morecomputer-readable media, such data and/or instruction-based expressionsof the above described circuits may be processed by a processing entity(e.g., one or more processors) within the computer system in conjunctionwith execution of one or more other computer programs including, withoutlimitation, net-list generation programs, place and route programs andthe like, to generate a representation or image of a physicalmanifestation of such circuits. Such representation or image maythereafter be used in device fabrication, for example, by enablinggeneration of one or more masks that are used to form various componentsof the circuits in a fabrication process.

Moreover, the various circuits and circuitry, as well as techniques,disclosed herein may be represented via simulations using computer aideddesign and/or testing tools. The simulation of the charging circuitry,control circuitry and/or monitoring circuitry, and/or techniquesimplemented thereby, may be implemented by a computer system whereincharacteristics and operations of such circuitry, and techniquesimplemented thereby, are imitated, replicated and/or predicted via acomputer system. The present inventions are also directed to suchsimulations of the inventive charging circuitry, control circuitryand/or monitoring circuitry, and/or techniques implemented thereby, and,as such, are intended to fall within the scope of the presentinventions. The computer-readable media corresponding to suchsimulations and/or testing tools are also intended to fall within thescope of the present inventions.

In the claims, the term “battery” means an individual cell (which storesenergy) and/or a plurality of cells arranged electrically in a seriesand/or parallel configuration.

Notably, the terms “first,” “second,” and the like, herein do not denoteany order, quantity, or importance, but rather are used to distinguishone element from another. Moreover, in the claims, the terms “a” and“an” herein do not denote a limitation of quantity, but rather denotethe presence of at least one of the referenced item.

1-20. (canceled)
 21. A method of controlling at least one characteristicof a charging process for a battery having positive and negativeterminals, the method comprising: (a) measuring a terminal voltagebetween the terminals of the battery multiple times or continuously overa period of time; (b) from the measurements of the terminal voltage in(a), determining a relaxation time of the battery; and (c) based on therelaxation time determined in (b), controlling at least onecharacteristic of a charging process for the battery.
 22. The method ofclaim 21, wherein the relaxation time is a full relaxation time.
 23. Themethod of claim 21, wherein controlling the at least one characteristicof the charging process for the battery comprises adjusting the at leastone characteristic so that the relaxation time is below a predeterminedvalue and/or within a predetermined range.
 24. The method of claim 23,wherein the predetermined value and/or predetermined range varies withstate of charge of the battery and/or state of health of the battery.25. The method of claim 21, wherein determining the relaxation time ofthe battery comprises determining from the measurements of the terminalvoltage a period of time between an excitation signal applied to thebattery terminals and a full or partial equilibrium state.
 26. Themethod of claim 25, wherein the excitation signal comprises a chargepulse.
 27. The method of claim 21, wherein determining the relaxationtime of the battery comprises determining from the measurements of theterminal voltage a period of time for the terminal voltage to drop todrop to a predetermined level and/or drop by a predetermined amountassociated equilibrium in the battery.
 28. The method of claim 21,wherein the at least one characteristic of the charging process for thebattery are characteristics of a current signal.
 29. The method of claim28, wherein the at least one characteristic is selected from the groupconsisting of an amplitude and/or a duration of the charge signal. 30.The method of claim 28, wherein the current signal comprises a pluralityof charge pulses and a plurality of discharge pulses.
 31. An apparatusto charge a battery including at least two terminals, the apparatuscomprising: current generation circuitry, coupled to the battery, to:generate a current signal, and apply the current signal to the battery;measuring circuitry, coupled to the battery, to measure a voltage at theterminals of the battery; and control circuitry, coupled to the chargingcircuitry and the measuring circuitry, and configured to (i) receivedata which is representative of the measured voltage, and (ii) outputone or more control signals to the current generation circuitry, whereinthe control circuitry is further configured to: (a) obtain the terminalvoltage measured multiple times or continuously over a period of time,(b) from the terminal voltages obtained in (a), determining a relaxationtime of the battery, and (c) based on the relaxation time determined in(b), control at least one characteristic of the current signal.
 32. Theapparatus of claim 31, wherein the relaxation time is a full relaxationtime.
 33. The apparatus of claim 31, wherein the control circuitry isconfigured such that controlling the at least one characteristic of thecharging process for the battery comprises adjusting the at least onecharacteristic so that the relaxation time is below a predeterminedvalue and/or within a predetermined range.
 34. The apparatus of claim33, wherein the predetermined value and/or predetermined range varieswith state of charge of the battery and/or state of health of thebattery.
 35. The apparatus of claim 31, wherein the control circuitry isconfigured such that determining the relaxation time of the batterycomprises determining from the measurements of the terminal voltage aperiod of time between an excitation signal applied to the batteryterminals and a full or partial equilibrium state.
 36. The apparatus ofclaim 35, wherein the excitation signal comprises a charge pulse. 37.The apparatus of claim 31, wherein the control circuitry is configuredsuch that determining the relaxation time of the battery comprisesdetermining from the measurements of the terminal voltage a period oftime for the terminal voltage to drop to drop to a predetermined leveland/or drop by a predetermined amount associated equilibrium in thebattery.
 38. The apparatus of claim 31, wherein the at least onecharacteristic is selected from the group consisting of an amplitudeand/or a duration of the current signal.
 39. The apparatus of claim 31,wherein the current signal comprises a plurality of charge pulses and aplurality of discharge pulses.